gray/src/equilibrium.f90

1304 lines
41 KiB
Fortran
Raw Normal View History

! This module handles the loading, interpolation and evaluation of the
! MHD equilibrium data (poloidal current function, safety factor,
! poloidal flux, magnetic field, etc.)
!
! Two kinds of data are supported: analytical (suffix `_an` in the
! subroutine names) or numerical (suffix `_spline`). For the latter, the
! the data is interpolated using splines.
2015-11-18 17:34:33 +01:00
module equilibrium
use const_and_precisions, only : wp_
use splines, only : spline_simple, spline_1d, spline_2d, linear_1d
2015-11-18 17:34:33 +01:00
implicit none
! Parameters of the analytical equilibrium model
type analytic_model
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
real(wp_) :: q0 ! Safety factor at the magnetic axis
real(wp_) :: q1 ! Safety factor at the edge
real(wp_) :: alpha ! Exponent for the q(ρ_p) power law
real(wp_) :: R0 ! R of the magnetic axis (m)
real(wp_) :: z0 ! z of the magnetic axis (m)
real(wp_) :: a ! Minor radius (m)
real(wp_) :: B0 ! Magnetic field at the magnetic axis (T)
end type
! Order of the splines
integer, parameter :: kspl=3, ksplp=kspl + 1
! Global variable storing the state of the module
! Splines
type(spline_1d), save :: fpol_spline ! Poloidal current function F(ψ)
type(spline_2d), save :: psi_spline ! Normalised poloidal flux ψ(R,z)
type(spline_simple), save :: q_spline ! Safey factor q(ψ)
type(linear_1d), save :: rhop_spline, rhot_spline ! Normalised radii ρ_p(ρ_t), ρ_t(ρ_p)
! Analytic model
type(analytic_model), save :: model
! More parameters
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
real(wp_), save :: fpolas ! Poloidal current at the edge (r=a), F_a
real(wp_), save :: psia ! Poloidal flux at the edge (r=a), ψ_a
real(wp_), save :: phitedge ! Toroidal flux at the edge
real(wp_), save :: btaxis ! B₀: B_φ = B₀R₀/R
real(wp_), save :: rmaxis, zmaxis ! R,z of the magnetic axis (O point)
real(wp_), save :: sgnbphi ! Sign of B_φ (>0 means CCW)
real(wp_), save :: btrcen ! used only for jcd_astra def.
real(wp_), save :: rcen ! Major radius R₀, computed as fpolas/btrcen
real(wp_), save :: rmnm, rmxm ! R interval of the equilibrium definition
real(wp_), save :: zmnm, zmxm ! z interval of the equilibrium definition
real(wp_), save :: zbinf, zbsup
private
public read_eqdsk, read_equil_an ! Reading data files
public scale_equil, change_cocos ! Transforming data
public equian ! Analytical model
public equinum_psi, equinum_fpol ! Interpolated data
public fq, bfield, tor_curr, tor_curr_psi ! Accessing local quantities
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
public frhotor, frhopol ! Converting between poloidal/toroidal flux
public set_equil_spline, set_equil_an ! Initialising internal state
public unset_equil_spline ! Deinitialising internal state
! Members exposed for magsurf_data
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
public kspl, psi_spline, q_spline, points_tgo, model
! Members exposed to gray_core and more
public psia, phitedge
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
public btaxis, rmaxis, zmaxis, sgnbphi
public btrcen, rcen
public rmnm, rmxm, zmnm, zmxm
public zbinf, zbsup
2015-11-18 17:34:33 +01:00
contains
2023-09-12 16:29:09 +02:00
subroutine read_eqdsk(params, data, err, unit)
! Reads the MHD equilibrium `data` from a G-EQDSK file (params%filenm).
! If given, the file is opened in the `unit` number.
! For a description of the G-EQDSK, see the GRAY user manual.
2015-11-18 17:34:33 +01:00
use const_and_precisions, only : one
use gray_params, only : equilibrium_parameters, equilibrium_data
use utils, only : get_free_unit
2021-12-18 18:57:38 +01:00
use logger, only : log_error
2015-11-18 17:34:33 +01:00
implicit none
! subroutine arguments
type(equilibrium_parameters), intent(in) :: params
type(equilibrium_data), intent(out) :: data
2023-09-12 16:29:09 +02:00
integer, intent(out) :: err
integer, optional, intent(in) :: unit
! local variables
integer :: u, idum, i, j, nr, nz, nbnd, nlim
2015-11-18 17:34:33 +01:00
character(len=48) :: string
real(wp_) :: dr, dz, dps, rleft, zmid, zleft, psiedge, psiaxis
real(wp_) :: xdum ! dummy variable, used to discard data
u = get_free_unit(unit)
2015-11-18 17:34:33 +01:00
! Open the G-EQDSK file
2021-12-18 18:57:38 +01:00
open(file=params%filenm, status='old', action='read', unit=u, iostat=err)
if (err /= 0) then
call log_error('opening eqdsk file ('//trim(params%filenm)//') failed!', &
mod='equilibrium', proc='read_eqdsk')
2023-09-12 16:29:09 +02:00
err = 1
return
2021-12-18 18:57:38 +01:00
end if
2015-11-18 17:34:33 +01:00
! get size of main arrays and allocate them
if (params%idesc == 1) then
2015-11-18 17:34:33 +01:00
read (u,'(a48,3i4)') string,idum,nr,nz
else
read (u,*) nr, nz
2015-11-18 17:34:33 +01:00
end if
if (allocated(data%rv)) deallocate(data%rv)
if (allocated(data%zv)) deallocate(data%zv)
if (allocated(data%psin)) deallocate(data%psin)
if (allocated(data%psinr)) deallocate(data%psinr)
if (allocated(data%fpol)) deallocate(data%fpol)
if (allocated(data%qpsi)) deallocate(data%qpsi)
allocate(data%rv(nr), data%zv(nz), &
data%psin(nr, nz), &
data%psinr(nr), &
data%fpol(nr), &
data%qpsi(nr))
! Store 0D data and main arrays
if (params%ifreefmt==1) then
read (u, *) dr, dz, data%rvac, rleft, zmid
read (u, *) data%rax, data%zax, psiaxis, psiedge, xdum
read (u, *) xdum, xdum, xdum, xdum, xdum
read (u, *) xdum, xdum, xdum, xdum, xdum
read (u, *) (data%fpol(i), i=1,nr)
read (u, *) (xdum,i=1, nr)
read (u, *) (xdum,i=1, nr)
read (u, *) (xdum,i=1, nr)
read (u, *) ((data%psin(i,j), i=1,nr), j=1,nz)
read (u, *) (data%qpsi(i), i=1,nr)
2015-11-18 17:34:33 +01:00
else
read (u, '(5e16.9)') dr,dz,data%rvac,rleft,zmid
read (u, '(5e16.9)') data%rax,data%zax,psiaxis,psiedge,xdum
read (u, '(5e16.9)') xdum,xdum,xdum,xdum,xdum
read (u, '(5e16.9)') xdum,xdum,xdum,xdum,xdum
read (u, '(5e16.9)') (data%fpol(i),i=1,nr)
read (u, '(5e16.9)') (xdum,i=1,nr)
read (u, '(5e16.9)') (xdum,i=1,nr)
read (u, '(5e16.9)') (xdum,i=1,nr)
read (u, '(5e16.9)') ((data%psin(i,j),i=1,nr),j=1,nz)
read (u, '(5e16.9)') (data%qpsi(i),i=1,nr)
2015-11-18 17:34:33 +01:00
end if
! Get size of boundary and limiter arrays and allocate them
read (u,*) nbnd, nlim
if (allocated(data%rbnd)) deallocate(data%rbnd)
if (allocated(data%zbnd)) deallocate(data%zbnd)
if (allocated(data%rlim)) deallocate(data%rlim)
if (allocated(data%zlim)) deallocate(data%zlim)
! Load plasma boundary data
if(nbnd > 0) then
allocate(data%rbnd(nbnd), data%zbnd(nbnd))
if (params%ifreefmt == 1) then
read(u, *) (data%rbnd(i), data%zbnd(i), i=1,nbnd)
2015-11-18 17:34:33 +01:00
else
read(u, '(5e16.9)') (data%rbnd(i), data%zbnd(i), i=1,nbnd)
2015-11-18 17:34:33 +01:00
end if
end if
! Load limiter data
if(nlim > 0) then
allocate(data%rlim(nlim), data%zlim(nlim))
if (params%ifreefmt == 1) then
read(u, *) (data%rlim(i), data%zlim(i), i=1,nlim)
2015-11-18 17:34:33 +01:00
else
read(u, '(5e16.9)') (data%rlim(i), data%zlim(i), i=1,nlim)
2015-11-18 17:34:33 +01:00
end if
end if
! End of G-EQDSK file
2015-11-18 17:34:33 +01:00
close(u)
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! Build rv,zv,psinr arrays
zleft = zmid-0.5_wp_*dz
dr = dr/(nr-1)
dz = dz/(nz-1)
dps = one/(nr-1)
2015-11-18 17:34:33 +01:00
do i=1,nr
data%psinr(i) = (i-1)*dps
data%rv(i) = rleft + (i-1)*dr
2015-11-18 17:34:33 +01:00
end do
do i=1,nz
data%zv(i) = zleft + (i-1)*dz
2015-11-18 17:34:33 +01:00
end do
! Normalize psin
data%psia = psiedge - psiaxis
if(params%ipsinorm == 0) data%psin = (data%psin - psiaxis)/data%psia
end subroutine read_eqdsk
2015-11-18 17:34:33 +01:00
2023-09-12 16:29:09 +02:00
subroutine read_equil_an(filenm, ipass, data, err, unit)
! Reads the MHD equilibrium `data` in the analytical format
! from params%filenm.
! If given, the file is opened in the `unit` number.
!
! TODO: add format description
use gray_params, only : equilibrium_data
use utils, only : get_free_unit
use logger, only : log_error
2021-12-18 18:57:38 +01:00
2015-11-18 17:34:33 +01:00
implicit none
! subroutine arguments
character(len=*), intent(in) :: filenm
integer, intent(in) :: ipass
type(equilibrium_data), intent(out) :: data
2023-09-12 16:29:09 +02:00
integer, intent(out) :: err
integer, optional, intent(in) :: unit
! local variables
integer :: i, u, nlim
2015-11-18 17:34:33 +01:00
u = get_free_unit(unit)
2021-12-18 18:57:38 +01:00
open(file=filenm, status='old', action='read', unit=u, iostat=err)
if (err /= 0) then
call log_error('opening equilibrium file ('//trim(filenm)//') failed!', &
mod='equilibrium', proc='read_equil_an')
2023-09-12 16:29:09 +02:00
err = 1
return
2021-12-18 18:57:38 +01:00
end if
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
read(u, *) model%R0, model%z0, model%a
read(u, *) model%B0
read(u, *) model%q0, model%q1, model%alpha
if(ipass >= 2) then
! get size of boundary and limiter arrays and allocate them
read (u,*) nlim
if (allocated(data%rlim)) deallocate(data%rlim)
if (allocated(data%zlim)) deallocate(data%zlim)
! store boundary and limiter data
if(nlim > 0) then
allocate(data%rlim(nlim), data%zlim(nlim))
read(u,*) (data%rlim(i), data%zlim(i), i = 1, nlim)
end if
end if
2015-11-18 17:34:33 +01:00
close(u)
end subroutine read_equil_an
subroutine change_cocos(data, cocosin, cocosout, error)
! Convert the MHD equilibrium data from one coordinate convention
! (COCOS) to another. These are specified by `cocosin` and
! `cocosout`, respectively.
!
! For more information, see: https://doi.org/10.1016/j.cpc.2012.09.010
use const_and_precisions, only : zero, one, pi
use gray_params, only : equilibrium_data
2015-11-18 17:34:33 +01:00
implicit none
! subroutine arguments
type(equilibrium_data), intent(inout) :: data
2015-11-18 17:34:33 +01:00
integer, intent(in) :: cocosin, cocosout
integer, intent(out), optional :: error
! local variables
real(wp_) :: isign, bsign
integer :: exp2pi, exp2piout
logical :: phiccw, psiincr, qpos, phiccwout, psiincrout, qposout
call decode_cocos(cocosin, exp2pi, phiccw, psiincr, qpos)
call decode_cocos(cocosout, exp2piout, phiccwout, psiincrout, qposout)
! Check sign consistency
isign = sign(one, data%psia)
if (.not.psiincr) isign = -isign
bsign = sign(one, data%fpol(size(data%fpol)))
if (qpos .neqv. isign * bsign * data%qpsi(size(data%qpsi)) > zero) then
! Warning: sign inconsistency found among q, Ipla and Bref
data%qpsi = -data%qpsi
if (present(error)) error = 1
2015-11-18 17:34:33 +01:00
else
if (present(error)) error = 0
2015-11-18 17:34:33 +01:00
end if
! Convert cocosin to cocosout
! Opposite direction of toroidal angle phi in cocosin and cocosout
if (phiccw .neqv. phiccwout) data%fpol = -data%fpol
! q has opposite sign for given sign of Bphi*Ip
if (qpos .neqv. qposout) data%qpsi = -data%qpsi
! psi and Ip signs don't change accordingly
if ((phiccw .eqv. phiccwout) .neqv. (psiincr .eqv. psiincrout)) &
data%psia = -data%psia
2015-11-18 17:34:33 +01:00
! Convert Wb to Wb/rad or viceversa
data%psia = data%psia * (2.0_wp_*pi)**(exp2piout - exp2pi)
2015-11-18 17:34:33 +01:00
end subroutine change_cocos
subroutine decode_cocos(cocos, exp2pi, phiccw, psiincr, qpos)
! Extracts the sign and units conventions from a COCOS index
2015-11-18 17:34:33 +01:00
implicit none
! subroutine arguments
integer, intent(in) :: cocos
2015-11-18 17:34:33 +01:00
integer, intent(out) :: exp2pi
logical, intent(out) :: phiccw, psiincr, qpos
! local variables
integer :: cmod10, cmod4
cmod10 = mod(cocos, 10)
cmod4 = mod(cmod10, 4)
! cocos>10 ψ in Wb, cocos<10 ψ in Wb/rad
exp2pi = (cocos - cmod10)/10
! cocos mod 10 = 1,3,5,7: toroidal angle φ increasing CCW
phiccw = (mod(cmod10, 2)== 1)
! cocos mod 10 = 1,2,5,6: ψ increasing with positive Ip
psiincr = (cmod4==1 .or. cmod4==2)
! cocos mod 10 = 1,2,7,8: q positive for positive Bφ*Ip
qpos = (cmod10<3 .or. cmod10>6)
2015-11-18 17:34:33 +01:00
end subroutine decode_cocos
subroutine scale_equil(params, data)
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! Rescale the magnetic field (B) and the plasma current (I_p)
! and/or force their signs.
!
! Notes:
! 1. signi and signb are ignored on input if equal to 0.
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! They are used to assign the direction of B_φ and I_p BEFORE scaling.
! 2. cocos=3 assumed: positive toroidal direction is CCW from above
! 3. B_φ and I_p scaled by the same factor factb to keep q unchanged
! 4. factb<0 reverses the directions of Bphi and Ipla
2015-11-18 17:34:33 +01:00
use const_and_precisions, only : one
use gray_params, only : equilibrium_parameters, equilibrium_data
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
use gray_params, only : iequil
2015-11-18 17:34:33 +01:00
implicit none
! subroutine arguments
type(equilibrium_parameters), intent(inout) :: params
type(equilibrium_data), intent(inout) :: data
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! Notes on cocos=3
! 1. With both I_p,B_φ > 0 we have ∂ψ/∂r<0 and ∂Φ/∂r>0.
! 2. ψ_a = ψ_edge - ψ_axis < 0.
! 3. q = 1/2π ∂Φ/∂ψ ~ ∂Φ/∂r⋅∂r/∂ψ < 0.
! 4. In general, sgn(q) = -sgn(I_p)⋅sgn(B_φ).
if (iequil < 2) then
! Analytical model
! Apply signs
if (params%sgni /= 0) then
model%q0 = sign(model%q0, -params%sgni*one)
model%q1 = sign(model%q1, -params%sgni*one)
end if
if (params%sgnb /= 0) then
model%B0 = sign(model%B0, +params%sgnb*one)
end if
! Rescale
model%B0 = model%B0 * params%factb
else
! Numeric data
! Apply signs
if (params%sgni /= 0) &
data%psia = sign(data%psia, -params%sgni*one)
if (params%sgnb /= 0) &
data%fpol = sign(data%fpol, +params%sgnb*one)
! Rescale
data%psia = data%psia * params%factb
data%fpol = data%fpol * params%factb
! Compute the signs to be shown in the outputs header when cocos≠0,10.
! Note: In these cases the values sgni,sgnb from gray.ini are unused.
params%sgni = int(sign(one, -data%psia))
params%sgnb = int(sign(one, +data%fpol(size(data%fpol))))
end if
end subroutine scale_equil
2015-11-18 17:34:33 +01:00
2023-09-12 16:29:09 +02:00
subroutine set_equil_spline(params, data, err)
! Computes splines for the MHD equilibrium data and stores them
! in their respective global variables, see the top of this file.
use const_and_precisions, only : zero, one
use gray_params, only : equilibrium_parameters, equilibrium_data
use gray_params, only : iequil
use reflections, only : inside
use utils, only : vmaxmin, vmaxmini
2021-12-18 18:57:38 +01:00
use logger, only : log_info
2015-11-18 17:34:33 +01:00
implicit none
! subroutine arguments
2023-09-12 16:29:09 +02:00
type(equilibrium_parameters), intent(in) :: params
type(equilibrium_data), intent(in) :: data
integer, intent(out) :: err
! local variables
integer :: nr, nz, nrest, nzest, npsest, nrz, npsi, nbnd, ibinf, ibsup
real(wp_) :: tension, rax0, zax0, psinoptmp, psinxptmp
real(wp_) :: rbmin, rbmax, rbinf, rbsup, r1, z1
real(wp_) :: psiant, psinop
real(wp_), dimension(size(data%psinr)) :: rhotn
real(wp_), dimension(:), allocatable :: rv1d, zv1d, fvpsi, wf
2023-09-12 16:29:09 +02:00
integer :: ixploc, info, i, j, ij
2021-12-18 18:57:38 +01:00
character(256) :: msg ! for log messages formatting
2015-11-18 17:34:33 +01:00
! compute array sizes
nr = size(data%rv)
nz = size(data%zv)
nrz = nr*nz
npsi = size(data%psinr)
nrest = nr + ksplp
nzest = nz + ksplp
npsest = npsi + ksplp
! length in m !!!
rmnm = data%rv(1)
rmxm = data%rv(nr)
zmnm = data%zv(1)
zmxm = data%zv(nz)
! Spline interpolation of ψ(R, z)
if (iequil>2) then
! data valid only inside boundary (data%psin=0 outside), e.g. source==ESCO
! presence of boundary anticipated here to filter invalid data
nbnd = min(size(data%rbnd), size(data%zbnd))
! allocate knots and spline coefficients arrays
if (allocated(psi_spline%knots_x)) deallocate(psi_spline%knots_x)
if (allocated(psi_spline%knots_y)) deallocate(psi_spline%knots_y)
if (allocated(psi_spline%coeffs)) deallocate(psi_spline%coeffs)
allocate(psi_spline%knots_x(nrest), psi_spline%knots_y(nzest))
allocate(psi_spline%coeffs(nrz))
! determine number of valid grid points
nrz=0
do j=1,nz
do i=1,nr
if (nbnd.gt.0) then
if(.not.inside(data%rbnd,data%zbnd,nbnd,data%rv(i),data%zv(j))) cycle
else
if(data%psin(i,j).le.0.0d0) cycle
end if
nrz=nrz+1
end do
end do
! store valid data
allocate(rv1d(nrz),zv1d(nrz),fvpsi(nrz),wf(nrz))
ij=0
do j=1,nz
do i=1,nr
if (nbnd.gt.0) then
if(.not.inside(data%rbnd,data%zbnd,nbnd,data%rv(i),data%zv(j))) cycle
else
if(data%psin(i,j).le.0.0d0) cycle
end if
ij=ij+1
rv1d(ij)=data%rv(i)
zv1d(ij)=data%zv(j)
fvpsi(ij)=data%psin(i,j)
wf(ij)=1.0d0
end do
end do
! Fit as a scattered set of points
! use reduced number of knots to limit memory comsumption ?
psi_spline%nknots_x=nr/4+4
psi_spline%nknots_y=nz/4+4
tension = params%ssplps
call scatterspl(rv1d, zv1d, fvpsi, wf, nrz, kspl, tension, &
rmnm, rmxm, zmnm, zmxm, &
psi_spline%knots_x, psi_spline%nknots_x, &
psi_spline%knots_y, psi_spline%nknots_y, &
2023-09-12 16:29:09 +02:00
psi_spline%coeffs, err)
! if failed, re-fit with an interpolating spline (zero tension)
2023-09-12 16:29:09 +02:00
if(err == -1) then
err = 0
tension = 0
psi_spline%nknots_x=nr/4+4
psi_spline%nknots_y=nz/4+4
call scatterspl(rv1d, zv1d, fvpsi, wf, nrz, kspl, tension, &
rmnm, rmxm, zmnm, zmxm, &
psi_spline%knots_x, psi_spline%nknots_x, &
psi_spline%knots_y, psi_spline%nknots_y, &
2023-09-12 16:29:09 +02:00
psi_spline%coeffs, err)
end if
deallocate(rv1d, zv1d, wf, fvpsi)
! reset nrz to the total number of grid points for next allocations
nrz = nr*nz
else
! iequil==2: data are valid on the full R,z grid
! reshape 2D ψ array to 1D (transposed)
allocate(fvpsi(nrz))
fvpsi = reshape(transpose(data%psin), [nrz])
! compute spline coefficients
call psi_spline%init(data%rv, data%zv, fvpsi, nr, nz, &
range=[rmnm, rmxm, zmnm, zmxm], &
2023-09-12 16:29:09 +02:00
tension=params%ssplps, err=err)
! if failed, re-fit with an interpolating spline (zero tension)
2023-09-12 16:29:09 +02:00
if(err == -1) then
call psi_spline%init(data%rv, data%zv, fvpsi, nr, nz, &
range=[rmnm, rmxm, zmnm, zmxm], &
tension=zero)
2023-09-12 16:29:09 +02:00
err = 0
end if
deallocate(fvpsi)
2015-11-18 17:34:33 +01:00
end if
2023-09-12 16:29:09 +02:00
if (err /= 0) then
err = 2
return
end if
! compute spline coefficients for ψ(R,z) partial derivatives
call psi_spline%init_deriv(nr, nz, 1, 0) ! ∂ψ/∂R
call psi_spline%init_deriv(nr, nz, 0, 1) ! ∂ψ/∂z
call psi_spline%init_deriv(nr, nz, 1, 1) ! ∂²ψ/∂R∂z
call psi_spline%init_deriv(nr, nz, 2, 0) ! ∂²ψ/∂R²
call psi_spline%init_deriv(nr, nz, 0, 2) ! ∂²ψ/∂z²
! Spline interpolation of F(ψ)
! give a small weight to the last point
2015-11-18 17:34:33 +01:00
allocate(wf(npsi))
wf(1:npsi-1) = 1
wf(npsi) = 1.0e2_wp_
call fpol_spline%init(data%psinr, data%fpol, npsi, range=[zero, one], &
weights=wf, tension=params%ssplf)
deallocate(wf)
! set vacuum value used outside 0 ≤ ψ ≤ 1 range
fpolas = fpol_spline%eval(data%psinr(npsi))
sgnbphi = sign(one ,fpolas)
! Re-normalize ψ_n after the spline computation
! Note: this ensures 0 ≤ ψ_n'(R,z) < 1 inside the plasma
2015-11-18 17:34:33 +01:00
! Start with un-corrected ψ_n
psia = data%psia
psinop = 0 ! ψ_n(O point)
psiant = 1 ! ψ_n(X point) - ψ_n(O point)
2015-11-18 17:34:33 +01:00
! Use provided boundary to set an initial guess
! for the search of O/X points
nbnd=min(size(data%rbnd), size(data%zbnd))
2015-11-18 17:34:33 +01:00
if (nbnd>0) then
call vmaxmini(data%zbnd,nbnd,zbinf,zbsup,ibinf,ibsup)
rbinf=data%rbnd(ibinf)
rbsup=data%rbnd(ibsup)
call vmaxmin(data%rbnd,nbnd,rbmin,rbmax)
2015-11-18 17:34:33 +01:00
else
zbinf=data%zv(2)
zbsup=data%zv(nz-1)
rbinf=data%rv((nr+1)/2)
2015-11-18 17:34:33 +01:00
rbsup=rbinf
rbmin=data%rv(2)
rbmax=data%rv(nr-1)
2015-11-18 17:34:33 +01:00
end if
! Search for exact location of the magnetic axis
rax0=data%rax
zax0=data%zax
2015-11-18 17:34:33 +01:00
call points_ox(rax0,zax0,rmaxis,zmaxis,psinoptmp,info)
2021-12-18 18:57:38 +01:00
write (msg, '("O-point found:", 3(x,a,"=",g0.3))') &
'r', rmaxis, 'z', zmaxis, 'ψ', psinoptmp
call log_info(msg, mod='equilibrium', proc='set_equil_spline')
2015-11-18 17:34:33 +01:00
! search for X-point if params%ixp /= 0
2015-11-18 17:34:33 +01:00
ixploc = params%ixp
2015-11-18 17:34:33 +01:00
if(ixploc/=0) then
if(ixploc<0) then
call points_ox(rbinf,zbinf,r1,z1,psinxptmp,info)
if(psinxptmp/=-1.0_wp_) then
2021-12-18 18:57:38 +01:00
write (msg, '("X-point found:", 3(x,a,"=",g0.3))') &
'r', r1, 'z', z1, 'ψ', psinxptmp
call log_info(msg, mod='equilibrium', proc='set_equil_spline')
2021-12-18 18:57:38 +01:00
2015-11-18 17:34:33 +01:00
zbinf=z1
psinop=psinoptmp
psiant=psinxptmp-psinop
call points_tgo(rmaxis,0.5_wp_*(zmaxis+zbsup),r1,z1,one,info)
zbsup=z1
else
ixploc=0
end if
else
call points_ox(rbsup,zbsup,r1,z1,psinxptmp,info)
if(psinxptmp.ne.-1.0_wp_) then
2021-12-18 18:57:38 +01:00
write (msg, '("X-point found:", 3(x,a,"=",g0.3))') &
'r', r1, 'z', z1, 'ψ', psinxptmp
call log_info(msg, mod='equilibrium', proc='set_equil_spline')
2021-12-18 18:57:38 +01:00
2015-11-18 17:34:33 +01:00
zbsup=z1
psinop=psinoptmp
psiant=psinxptmp-psinop
call points_tgo(rmaxis,0.5_wp_*(zmaxis+zbinf),r1,z1,one,info)
zbinf=z1
else
ixploc=0
end if
end if
end if
if (ixploc==0) then
psinop=psinoptmp
psiant=one-psinop
! Find upper horizontal tangent point
2015-11-18 17:34:33 +01:00
call points_tgo(rmaxis,0.5_wp_*(zmaxis+zbsup),r1,z1,one,info)
zbsup=z1
rbsup=r1
! Find lower horizontal tangent point
2015-11-18 17:34:33 +01:00
call points_tgo(rmaxis,0.5_wp_*(zmaxis+zbinf),r1,z1,one,info)
zbinf=z1
rbinf=r1
2021-12-18 18:57:38 +01:00
write (msg, '("X-point not found in", 2(x,a,"∈[",g0.3,",",g0.3,"]"))') &
'r', rbinf, rbsup, 'z', zbinf, zbsup
call log_info(msg, mod='equilibrium', proc='set_equil_spline')
2015-11-18 17:34:33 +01:00
end if
! Adjust all the B-spline coefficients
! Note: since ψ_n(R,z) = Σ_ij c_ij B_i(R)B_j(z), to correct ψ_n
! it's enough to correct (shift and scale) the c_ij
psi_spline%coeffs = (psi_spline%coeffs - psinop) / psiant
! Same for the derivatives
psi_spline%partial(1,0)%ptr = psi_spline%partial(1,0)%ptr / psiant
psi_spline%partial(0,1)%ptr = psi_spline%partial(0,1)%ptr / psiant
psi_spline%partial(2,0)%ptr = psi_spline%partial(2,0)%ptr / psiant
psi_spline%partial(0,2)%ptr = psi_spline%partial(0,2)%ptr / psiant
psi_spline%partial(1,1)%ptr = psi_spline%partial(1,1)%ptr / psiant
! Do the opposite scaling to preserve un-normalised values
! Note: this is only used for the poloidal magnetic field
psia = psia * psiant
! Save Bt value on axis (required in flux_average and used in Jcd def)
! and vacuum value B0 at ref. radius data%rvac (used in Jcd_astra def)
2015-11-18 17:34:33 +01:00
call equinum_fpol(zero, btaxis)
btaxis = btaxis/rmaxis
btrcen = fpolas/data%rvac
rcen = data%rvac
2021-12-18 18:57:38 +01:00
write (msg, '(2(a,g0.3))') 'Bt_center=', btrcen, ' Bt_axis=', btaxis
call log_info(msg, mod='equilibrium', proc='set_equil_spline')
! Compute ρ_p/ρ_t mapping based on the input q profile
call setqphi_num(data%psinr, abs(data%qpsi), abs(psia), rhotn)
call set_rho_spline(sqrt(data%psinr), rhotn)
end subroutine set_equil_spline
2015-11-18 17:34:33 +01:00
subroutine scatterspl(x,y,z,w,n,kspl,sspl,xmin,xmax,ymin,ymax, &
tx,nknt_x,ty,nknt_y,coeff,ierr)
! Computes the spline interpolation of a surface when
! the data points are irregular, i.e. not on a uniform grid
use const_and_precisions, only : comp_eps
use dierckx, only : surfit
2015-11-18 17:34:33 +01:00
implicit none
! subroutine arguments
integer, intent(in) :: n
real(wp_), dimension(n), intent(in) :: x, y, z
real(wp_), dimension(n), intent(in) :: w
integer, intent(in) :: kspl
real(wp_), intent(in) :: sspl
real(wp_), intent(in) :: xmin, xmax, ymin, ymax
real(wp_), dimension(nknt_x), intent(inout) :: tx
real(wp_), dimension(nknt_y), intent(inout) :: ty
integer, intent(inout) :: nknt_x, nknt_y
real(wp_), dimension(nknt_x*nknt_y), intent(out) :: coeff
integer, intent(out) :: ierr
! local variables
integer :: iopt
real(wp_) :: resid
integer :: u,v,km,ne,b1,b2,lwrk1,lwrk2,kwrk,nxest,nyest
real(wp_), dimension(:), allocatable :: wrk1, wrk2
integer, dimension(:), allocatable :: iwrk
nxest=nknt_x
nyest=nknt_y
ne = max(nxest,nyest)
km = kspl+1
u = nxest-km
v = nyest-km
b1 = kspl*min(u,v)+kspl+1
b2 = (kspl+1)*min(u,v)+1
lwrk1 = u*v*(2+b1+b2)+2*(u+v+km*(n+ne)+ne-2*kspl)+b2+1
lwrk2 = u*v*(b2+1)+b2
kwrk = n+(nknt_x-2*kspl-1)*(nknt_y-2*kspl-1)
allocate(wrk1(lwrk1),wrk2(lwrk2),iwrk(kwrk))
iopt=0
call surfit(iopt,n,x,y,z,w,xmin,xmax,ymin,ymax,kspl,kspl, &
sspl,nxest,nyest,ne,comp_eps,nknt_x,tx,nknt_y,ty, &
coeff,resid,wrk1,lwrk1,wrk2,lwrk2,iwrk,kwrk,ierr)
deallocate(wrk1,wrk2,iwrk)
end subroutine scatterspl
subroutine setqphi_num(psinq,q,psia,rhotn)
! Computes the spline of the safety factor q(ψ)
use const_and_precisions, only : pi
implicit none
! subroutine arguments
real(wp_), dimension(:), intent(in) :: psinq,q
real(wp_), intent(in) :: psia
real(wp_), dimension(:), intent(out), optional :: rhotn
! local variables
real(wp_), dimension(size(q)) :: phit
real(wp_) :: dx
integer :: k
call q_spline%init(psinq, q, size(q))
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! Toroidal flux as Φ(ψ) = 2π ∫q(ψ)dψ
phit(1)=0
do k=1,q_spline%ndata-1
dx=q_spline%data(k+1)-q_spline%data(k)
phit(k+1)=phit(k) + dx*(q_spline%coeffs(k,1) + dx*(q_spline%coeffs(k,2)/2 + &
dx*(q_spline%coeffs(k,3)/3 + dx* q_spline%coeffs(k,4)/4) ) )
end do
phitedge=phit(q_spline%ndata)
if(present(rhotn)) rhotn(1:q_spline%ndata)=sqrt(phit/phitedge)
phitedge=2*pi*psia*phitedge
end subroutine setqphi_num
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
subroutine set_equil_an
! Computes the analytical equilibrium data and stores them
! in their respective global variables, see the top of this file.
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
use const_and_precisions, only : pi, one
implicit none
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
real(wp_) :: dq
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
btaxis = model%B0
rmaxis = model%R0
zmaxis = model%z0
btrcen = model%B0
rcen = model%R0
zbinf = model%z0 - model%a
zbsup = model%z0 + model%a
sgnbphi = sign(one, model%B0)
rmxm = model%R0 + model%a
rmnm = model%R0 - model%a
zmxm = zbsup
zmnm = zbinf
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
phitedge = model%B0 * pi * model%a**2
dq = (model%q1 - model%q0) / (model%alpha/2 + 1)
psia = 1/(2*pi) * phitedge / (model%q0 + dq)
end subroutine set_equil_an
subroutine set_rho_spline(rhop, rhot)
! Computes the splines for converting between the poloidal (ρ_p)
! and toroidal (ρ_t) normalised radii
implicit none
! subroutine arguments
real(wp_), dimension(:), intent(in) :: rhop, rhot
call rhop_spline%init(rhot, rhop, size(rhop))
call rhot_spline%init(rhop, rhot, size(rhot))
end subroutine set_rho_spline
subroutine equinum_psi(R, z, psi, dpsidr, dpsidz, &
ddpsidrr, ddpsidzz, ddpsidrz)
! Computes the normalised poloidal flux ψ (and its derivatives)
! as a function of (R, z) using the numerical equilibrium
2015-11-18 17:34:33 +01:00
implicit none
! subroutine arguments
real(wp_), intent(in) :: R, z
real(wp_), intent(out), optional :: psi, dpsidr, dpsidz
real(wp_), intent(out), optional :: ddpsidrr, ddpsidzz, ddpsidrz
! Note: here lengths are measured in meters
if (R <= rmxm .and. R >= rmnm .and. &
z <= zmxm .and. z >= zmnm) then
if (present(psi)) psi = psi_spline%eval(R, z)
if (present(dpsidr)) dpsidr = psi_spline%deriv(R, z, 1, 0)
if (present(dpsidz)) dpsidz = psi_spline%deriv(R, z, 0, 1)
if (present(ddpsidrr)) ddpsidrr = psi_spline%deriv(R, z, 2, 0)
if (present(ddpsidzz)) ddpsidzz = psi_spline%deriv(R, z, 0, 2)
if (present(ddpsidrz)) ddpsidrz = psi_spline%deriv(R, z, 1, 1)
2015-11-18 17:34:33 +01:00
else
if (present(psi)) psi = -1
if (present(dpsidr)) dpsidr = 0
if (present(dpsidz)) dpsidz = 0
if (present(ddpsidrr)) ddpsidrr = 0
if (present(ddpsidzz)) ddpsidzz = 0
if (present(ddpsidrz)) ddpsidrz = 0
2015-11-18 17:34:33 +01:00
end if
end subroutine equinum_psi
subroutine equinum_fpol(psi, fpol, dfpol)
! Computes the poloidal current function F(ψ)
! (and its derivative) using the numerical equilibrium
2015-11-18 17:34:33 +01:00
implicit none
! subroutine arguments
real(wp_), intent(in) :: psi
real(wp_), intent(out) :: fpol
real(wp_), intent(out), optional :: dfpol
if(psi <= 1 .and. psi >= 0) then
fpol = fpol_spline%eval(psi)
if (present(dfpol)) dfpol = fpol_spline%deriv(psi) / psia
2015-11-18 17:34:33 +01:00
else
fpol = fpolas
if (present(dfpol)) dfpol = 0
2015-11-18 17:34:33 +01:00
end if
end subroutine equinum_fpol
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
subroutine equian(R, z, psin, fpolv, dfpv, dpsidr, dpsidz, &
ddpsidrr, ddpsidzz, ddpsidrz)
! Computes all MHD equilibrium parameters from a simple analytical model
2015-11-18 17:34:33 +01:00
implicit none
! subroutine arguments
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
real(wp_), intent(in) :: R, z
real(wp_), intent(out), optional :: psin, fpolv, dfpv, dpsidr, dpsidz, &
ddpsidrr, ddpsidzz, ddpsidrz
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! variables
real(wp_) :: r_p ! poloidal radius
real(wp_) :: rho_p ! poloidal radius normalised
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! ρ_p is just the geometrical poloidal radius divided by a
r_p = hypot(R - model%R0, z - model%z0)
rho_p = r_p / model%a
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! ψ_n = ρ_p²(R,z) = [(R-R₀)² + (z-z₀)²]/a²
if (present(psin)) psin = rho_p**2
2015-11-18 17:34:33 +01:00
! ∂ψ/∂R, ∂ψ/∂z
if (present(dpsidr)) dpsidr = 2*(R - model%R0)/model%a**2
if (present(dpsidz)) dpsidz = 2*(z - model%z0)/model%a**2
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! ∂²ψ/∂R², ∂²ψ/∂z², ∂²ψ/∂R∂z
if (present(ddpsidrr)) ddpsidrr = 2/model%a**2
if (present(ddpsidzz)) ddpsidzz = 2/model%a**2
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
if (present(ddpsidrz)) ddpsidrz = 0
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! F(ψ) = B₀⋅R₀, a constant
if (present(fpolv)) fpolv = model%B0 * model%R0
if (present(dfpv)) dfpv = 0
end subroutine equian
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
function frhotor(rho_p)
! Converts from poloidal (ρ_p) to toroidal (ρ_t) normalised radius
use gray_params, only : iequil
2015-11-18 17:34:33 +01:00
implicit none
! function arguments
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
real(wp_), intent(in) :: rho_p
real(wp_) :: frhotor
2015-11-18 17:34:33 +01:00
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
if (iequil < 2) then
! Analytical model
block
! The change of variable is obtained by integrating
!
! q(ψ) = 1/2π ∂Φ/∂ψ
!
! and defining ψ = ψ_a ρ_p², Φ = Φ_a ρ_t².
! The result is:
!
! - ψ_a = 1/2π Φ_a / [q₀ + Δq]
!
! - ρ_t = ρ_p √[(q₀ + Δq ρ_p^α)/(q₀ + Δq)]
!
! where Δq = (q₁ - q₀)/(α/2 + 1)
real(wp_) :: dq
dq = (model%q1 - model%q0) / (model%alpha/2 + 1)
frhotor = rho_p * sqrt((model%q0 + dq*rho_p**model%alpha) &
/ (model%q0 + dq))
end block
else
! Numerical data
frhotor = rhot_spline%eval(rho_p)
end if
end function frhotor
2015-11-18 17:34:33 +01:00
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
function frhopol(rho_t)
! Converts from toroidal (ρ_t) to poloidal (ρ_p) normalised radius
use gray_params, only : iequil
use const_and_precisions, only : comp_eps
implicit none
! function arguments
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
real(wp_), intent(in) :: rho_t
real(wp_) :: frhopol
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
if (iequil < 2) then
! Analytical model
block
! In general there is no closed form for ρ_p(ρ_t) in the
! analytical model, we thus solve numerically the equation
! ρ_t(ρ_p) = ρ_t₀ for ρ_p.
use minpack, only : hybrj1
real(wp_) :: rho_p(1), fvec(1), fjac(1,1), wa(7)
integer :: info
rho_p = [rho_t] ! first guess, ρ_p ≈ ρ_t
call hybrj1(equation, n=1, x=rho_p, fvec=fvec, fjac=fjac, &
ldfjac=1, tol=comp_eps, info=info, wa=wa, lwa=7)
frhopol = rho_p(1)
end block
else
! Numerical data
frhopol = rhop_spline%eval(rho_t)
end if
2015-11-18 17:34:33 +01:00
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
contains
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
subroutine equation(n, x, f, df, ldf, flag)
! The equation to solve: f(x) = ρ_t(x) - ρ_t₀ = 0
implicit none
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! optimal step size
real(wp_), parameter :: e = comp_eps**(1/3.0_wp_)
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! subroutine arguments
integer, intent(in) :: n, ldf, flag
real(wp_), intent(in) :: x(n)
real(wp_), intent(inout) :: f(n), df(ldf,n)
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
if (flag == 1) then
! return f(x)
f(1) = frhotor(x(1)) - rho_t
else
! return f'(x), computed numerically
df(1,1) = (frhotor(x(1) + e) - frhotor(x(1) - e)) / (2*e)
end if
end subroutine
end function frhopol
2015-11-18 17:34:33 +01:00
function fq(psin)
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! Computes the safety factor q as a function of the normalised
! poloidal flux ψ.
!
! Note: this returns the absolute value of q.
2015-11-18 17:34:33 +01:00
use gray_params, only : iequil
2015-11-18 17:34:33 +01:00
implicit none
! function arguments
2015-11-18 17:34:33 +01:00
real(wp_), intent(in) :: psin
real(wp_) :: fq
if (iequil < 2) then
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! Analytical model
! The safety factor is a power law in ρ_p:
! q(ρ_p) = q₀ + (q₁-q₀) ρ_p^α
block
real(wp_) :: rho_p
rho_p = sqrt(psin)
fq = abs(model%q0 + (model%q1 - model%q0) * rho_p**model%alpha)
end block
2015-11-18 17:34:33 +01:00
else
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! Numerical data
fq = q_spline%eval(psin)
2015-11-18 17:34:33 +01:00
end if
end function fq
subroutine bfield(rpsim, zpsim, bphi, br, bz)
! Computes the magnetic field as a function of
! (R, z) in cylindrical coordinates
use gray_params, only : iequil
2015-11-18 17:34:33 +01:00
implicit none
! subroutine arguments
real(wp_), intent(in) :: rpsim, zpsim
real(wp_), intent(out), optional :: bphi,br,bz
! local variables
real(wp_) :: psin,fpol
2015-11-18 17:34:33 +01:00
if (iequil < 2) then
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! Analytical model
call equian(rpsim,zpsim,fpolv=bphi,dpsidr=bz,dpsidz=br)
if (present(bphi)) bphi=bphi/rpsim
else
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! Numerical data
call equinum_psi(rpsim,zpsim,psi=bphi,dpsidr=bz,dpsidz=br)
if (present(bphi)) then
psin=bphi
call equinum_fpol(psin,fpol)
bphi=fpol/rpsim
end if
end if
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
if (present(br)) br=-br/rpsim
if (present(bz)) bz= bz/rpsim
end subroutine bfield
2015-11-18 17:34:33 +01:00
function tor_curr(rpsim,zpsim) result(jphi)
! Computes the toroidal current Jφ as a function of (R, z)
use const_and_precisions, only : ccj=>mu0inv
use gray_params, only : iequil
2015-11-18 17:34:33 +01:00
implicit none
! function arguments
real(wp_), intent(in) :: rpsim, zpsim
real(wp_) :: jphi
! local variables
real(wp_) :: bzz,dbvcdc13,dbvcdc31
real(wp_) :: dpsidr,ddpsidrr,ddpsidzz
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
if(iequil < 2) then
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! Analytical model
call equian(rpsim,zpsim,dpsidr=dpsidr, &
ddpsidrr=ddpsidrr,ddpsidzz=ddpsidzz)
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
else
! Numerical data
call equinum_psi(rpsim,zpsim,dpsidr=dpsidr, &
ddpsidrr=ddpsidrr,ddpsidzz=ddpsidzz)
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
end if
bzz= dpsidr/rpsim
dbvcdc13=-ddpsidzz/rpsim
dbvcdc31= ddpsidrr/rpsim-bzz/rpsim
jphi=ccj*(dbvcdc13-dbvcdc31)
end function tor_curr
function tor_curr_psi(psin) result(jphi)
! Computes the toroidal current Jφ as a function of ψ
implicit none
2015-11-18 17:34:33 +01:00
! function arguments
real(wp_), intent(in) :: psin
real(wp_) :: jphi
! local variables
real(wp_) :: r1, r2
call psi_raxis(psin, r1, r2)
jphi = tor_curr(r2, zmaxis)
end function tor_curr_psi
2015-11-18 17:34:33 +01:00
subroutine psi_raxis(psin,r1,r2)
2021-12-18 18:57:38 +01:00
use gray_params, only : iequil
use dierckx, only : profil, sproota
use logger, only : log_error
2015-11-18 17:34:33 +01:00
implicit none
2021-12-18 18:57:38 +01:00
! subroutine arguments
real(wp_) :: psin,r1,r2
2021-12-18 18:57:38 +01:00
! local constants
integer, parameter :: mest=4
! local variables
integer :: iopt,ier,m
real(wp_) :: zc,val
real(wp_), dimension(mest) :: zeroc
real(wp_), dimension(psi_spline%nknots_x) :: czc
2021-12-18 18:57:38 +01:00
character(64) :: msg
2015-11-18 17:34:33 +01:00
if (iequil < 2) then
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! Analytical model
val = sqrt(psin)
r1 = model%R0 - val*model%a
r2 = model%R0 + val*model%a
else
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
! Numerical data
iopt=1
zc=zmaxis
call profil(iopt, psi_spline%knots_x, psi_spline%nknots_x, &
psi_spline%knots_y, psi_spline%nknots_y, &
psi_spline%coeffs, kspl, kspl, zc, &
psi_spline%nknots_x, czc, ier)
2021-12-18 18:57:38 +01:00
if (ier > 0) then
write (msg, '("profil failed with error ",g0)') ier
call log_error(msg, mod='equilibrium', proc='psi_raxis')
end if
call sproota(psin, psi_spline%knots_x, psi_spline%nknots_x, &
czc, zeroc, mest, m, ier)
r1=zeroc(1)
r2=zeroc(2)
rework the analytical model This change modifies the analytical equilibrium in order to simplify the computation of the poloidal flux normalization and the derivatives. In the power law parametrisation of the safety factor, ρ_t is replaced with ρ_p and, similarly, the normalised poloidal radius is now identified with ρ_p, instead of ρ_t. With the same parameters (q₀,q₁,α...), this choice slightly changes the plasma current distribution, but enables us to obtain a closed form for ψ_a = ψ(r=a) and the relation ρ_t(ρ_p). In fact, both expressions are now obtained by integrating the q(ρ_p), instead of 1/q(ρ_t), which has no elementary antiderivative. As the normalisation is now computed exactly, the values of the normalised flux ψ_n = ψ/ψ_a and the gradient ∇ψ (entering the raytracing equations in X and ∇X, respectively) are computed to the same precision. Previously, ψ_n was computed to a lower precision due to the use of a simple trapezoid integration of 1/q(ρ_p) for ψ_a, while ∇ψ was computed up to machine precision using an exact formula. This error effectively caused a very slight decoupling between X=ω_p²/ω² and ∇X that introduced a systematic error in the numerical solution of the raytracing equations. The error manifests itself as a bias with a weak dependency on X in the values taken by the dispersion function Λ(r̅, n̅) on the phase-space points generated by the integrator. More specifically, lim h→0 Λ(r̅_i, n̅_i) = -kX(r̅_i) where h is the integrator step size; r̅_i is the position at the i-th step; k ≈ -3.258⋅10⁻⁵ and depends only on the number of points used to perform the trapedoid integral for ψ_a (as ~ 1/n²). After this change Λ behaves consistently with being a conserved quantity (zero) up to the cumulative integration error of the 4° order Runge-Kutta method. In fact we now have that: Λ(r̅_i, n̅_i) ∝ - h⁴ ‖∂⁴X(r̅_i)/∂r̅⁴‖ It must be said that within this model the relation ρ_p(ρ_t) can't be computed analytically (inverting ρ_t(ρ_p) produces a trascendental equation of the form b = x + c x^α). However, this relation is not necessary for raytracing and is easily solved, up to machine precision, using minpack. In addition, this change also makes the model consistetly use the cocos=3 and fully implements the ability to force the signs of I_p, B_φ (via equilibrium.sgni,sgnb) and rescaling the field (via equilibrium.factb).
2023-10-11 17:29:24 +02:00
end if
end subroutine psi_raxis
2015-11-18 17:34:33 +01:00
2015-11-18 17:34:33 +01:00
subroutine points_ox(rz,zz,rf,zf,psinvf,info)
! Finds the location of the O,X points
2015-11-18 17:34:33 +01:00
use const_and_precisions, only : comp_eps
2021-12-18 18:57:38 +01:00
use minpack, only : hybrj1
use logger, only : log_error, log_debug
2015-11-18 17:34:33 +01:00
implicit none
2021-12-18 18:57:38 +01:00
! local constants
2015-11-18 17:34:33 +01:00
integer, parameter :: n=2,ldfjac=n,lwa=(n*(n+13))/2
2021-12-18 18:57:38 +01:00
! arguments
2015-11-18 17:34:33 +01:00
real(wp_), intent(in) :: rz,zz
real(wp_), intent(out) :: rf,zf,psinvf
integer, intent(out) :: info
2021-12-18 18:57:38 +01:00
! local variables
2015-11-18 17:34:33 +01:00
real(wp_) :: tol
real(wp_), dimension(n) :: xvec,fvec
real(wp_), dimension(lwa) :: wa
real(wp_), dimension(ldfjac,n) :: fjac
2021-12-18 18:57:38 +01:00
character(256) :: msg
2015-11-18 17:34:33 +01:00
xvec(1)=rz
xvec(2)=zz
tol = sqrt(comp_eps)
call hybrj1(fcnox,n,xvec,fvec,fjac,ldfjac,tol,info,wa,lwa)
2021-12-18 18:57:38 +01:00
if(info /= 1) then
write (msg, '("O,X coordinates:",2(x,", ",g0.3))') xvec
call log_debug(msg, mod='equilibrium', proc='points_ox')
write (msg, '("hybrj1 failed with error ",g0)') info
call log_error(msg, mod='equilibrium', proc='points_ox')
end if
rf=xvec(1)
zf=xvec(2)
call equinum_psi(rf,zf,psinvf)
2015-11-18 17:34:33 +01:00
end subroutine points_ox
2015-11-18 17:34:33 +01:00
subroutine fcnox(n,x,fvec,fjac,ldfjac,iflag)
2021-12-18 18:57:38 +01:00
use logger, only : log_error
2015-11-18 17:34:33 +01:00
implicit none
2021-12-18 18:57:38 +01:00
! subroutine arguments
2015-11-18 17:34:33 +01:00
integer, intent(in) :: n,iflag,ldfjac
real(wp_), dimension(n), intent(in) :: x
real(wp_), dimension(n), intent(inout) :: fvec
real(wp_), dimension(ldfjac,n), intent(inout) :: fjac
2021-12-18 18:57:38 +01:00
! local variables
2015-11-18 17:34:33 +01:00
real(wp_) :: dpsidr,dpsidz,ddpsidrr,ddpsidzz,ddpsidrz
2021-12-18 18:57:38 +01:00
character(64) :: msg
2015-11-18 17:34:33 +01:00
select case(iflag)
case(1)
call equinum_psi(x(1),x(2),dpsidr=dpsidr,dpsidz=dpsidz)
fvec(1) = dpsidr
fvec(2) = dpsidz
2015-11-18 17:34:33 +01:00
case(2)
call equinum_psi(x(1),x(2),ddpsidrr=ddpsidrr,ddpsidzz=ddpsidzz, &
ddpsidrz=ddpsidrz)
fjac(1,1) = ddpsidrr
fjac(1,2) = ddpsidrz
fjac(2,1) = ddpsidrz
fjac(2,2) = ddpsidzz
2015-11-18 17:34:33 +01:00
case default
2021-12-18 18:57:38 +01:00
write (msg, '("invalid iflag: ",g0)')
call log_error(msg, mod='equilibrium', proc='fcnox')
2015-11-18 17:34:33 +01:00
end select
end subroutine fcnox
2015-11-18 17:34:33 +01:00
subroutine points_tgo(rz,zz,rf,zf,psin0,info)
use const_and_precisions, only : comp_eps
2021-12-18 18:57:38 +01:00
use minpack, only : hybrj1mv
use logger, only : log_error, log_debug
2015-11-18 17:34:33 +01:00
implicit none
2021-12-18 18:57:38 +01:00
! local constants
2015-11-18 17:34:33 +01:00
integer, parameter :: n=2,ldfjac=n,lwa=(n*(n+13))/2
2021-12-18 18:57:38 +01:00
! arguments
2015-11-18 17:34:33 +01:00
real(wp_), intent(in) :: rz,zz,psin0
real(wp_), intent(out) :: rf,zf
integer, intent(out) :: info
2021-12-18 18:57:38 +01:00
character(256) :: msg
! local variables
2015-11-18 17:34:33 +01:00
real(wp_) :: tol
real(wp_), dimension(n) :: xvec,fvec,f0
real(wp_), dimension(lwa) :: wa
real(wp_), dimension(ldfjac,n) :: fjac
xvec(1)=rz
xvec(2)=zz
f0(1)=psin0
f0(2)=0.0_wp_
tol = sqrt(comp_eps)
call hybrj1mv(fcntgo,n,xvec,f0,fvec,fjac,ldfjac,tol,info,wa,lwa)
2021-12-18 18:57:38 +01:00
if(info /= 1) then
write (msg, '("R,z coordinates:",5(x,g0.3))') xvec, rz, zz, psin0
call log_debug(msg, mod='equilibrium', proc='points_tgo')
write (msg, '("hybrj1mv failed with error ",g0)') info
call log_error(msg, mod='equilibrium', proc='points_tgo')
2015-11-18 17:34:33 +01:00
end if
rf=xvec(1)
zf=xvec(2)
end
2015-11-18 17:34:33 +01:00
subroutine fcntgo(n,x,f0,fvec,fjac,ldfjac,iflag)
use logger, only : log_error
2021-12-18 18:57:38 +01:00
2015-11-18 17:34:33 +01:00
implicit none
2021-12-18 18:57:38 +01:00
! subroutine arguments
2015-11-18 17:34:33 +01:00
integer, intent(in) :: n,ldfjac,iflag
real(wp_), dimension(n), intent(in) :: x,f0
real(wp_), dimension(n), intent(inout) :: fvec
real(wp_), dimension(ldfjac,n), intent(inout) :: fjac
2021-12-18 18:57:38 +01:00
! local variables
2015-11-18 17:34:33 +01:00
real(wp_) :: psinv,dpsidr,dpsidz,ddpsidrr,ddpsidrz
2021-12-18 18:57:38 +01:00
character(64) :: msg
2015-11-18 17:34:33 +01:00
select case(iflag)
case(1)
call equinum_psi(x(1),x(2),psinv,dpsidr)
fvec(1) = psinv-f0(1)
fvec(2) = dpsidr-f0(2)
2015-11-18 17:34:33 +01:00
case(2)
call equinum_psi(x(1),x(2),dpsidr=dpsidr,dpsidz=dpsidz, &
ddpsidrr=ddpsidrr,ddpsidrz=ddpsidrz)
fjac(1,1) = dpsidr
fjac(1,2) = dpsidz
fjac(2,1) = ddpsidrr
fjac(2,2) = ddpsidrz
2015-11-18 17:34:33 +01:00
case default
2021-12-18 18:57:38 +01:00
write (msg, '("invalid iflag: ",g0)')
call log_error(msg, mod='equilibrium', proc='fcntgo')
2015-11-18 17:34:33 +01:00
end select
end subroutine fcntgo
subroutine unset_equil_spline
! Unsets the splines global variables, see the top of this file.
2015-11-18 17:34:33 +01:00
implicit none
call fpol_spline%deinit
call psi_spline%deinit
call q_spline%deinit
call rhop_spline%deinit
call rhot_spline%deinit
end subroutine unset_equil_spline
2015-11-18 17:34:33 +01:00
end module equilibrium