gray/src/multipass.f90
Michele Guerini Rocco 0a87a3ef76
src/polarization.f90: rewrite
- Remove the Stokes parameters as an intermediate step in the
  conversion between Jones vectors and polarisation ellipses.

- Document every single step performed when converting between
  different parametrisations and how the polarisation at the
  plasma boundary is computed. This includes how everything
  was derived from first principles.

- Mark the subroutines as pure.

- Remove `set_pol` entirely.
2024-04-11 21:49:52 +02:00

293 lines
15 KiB
Fortran

module multipass
use const_and_precisions, only : wp_, zero, half, one, degree, czero
use beamdata, only : dst, nray
use gray_params, only : ipass
use polarization, only : pol_limit, field_to_ellipse
use reflections, only : wall_refl
use equilibrium, only : bfield
implicit none
integer, save :: nbeam_max ! max n of beams active at a time
integer, save :: nbeam_tot ! total n of beams
contains
subroutine plasma_in(i, x, N, Bres, sox, cpl, psi, chi, iop, ext, eyt, perfect)
! Computes the ray polarisation and power couplings when it enteres the plasma
use const_and_precisions, only: cm
! subroutine arguments
integer, intent(in) :: i ! ray index
real(wp_), intent(in) :: x(3), N(3) ! position, refactive index
real(wp_), intent(in) :: Bres ! resonant B field
integer, intent(in) :: sox ! sign of polarisation mode: -1 ⇒ O, +1 ⇒ X
real(wp_), intent(out) :: cpl(2) ! power coupling vector (O, X)
real(wp_), intent(out) :: psi, chi ! polarisation ellipse angles
integer, intent(inout), pointer :: iop(:) ! inside/outside plasma flag
complex(wp_), intent(inout), pointer :: ext(:), eyt(:) ! ray polarisation vector (e_x, e_y)
logical, intent(in) :: perfect ! whether to assume perfect coupling
! local variables
real(wp_) :: R, z, cosphi, sinphi, B_phi, B_R, B_z
real(wp_) :: B(3)
real(wp_) :: c
complex(wp_) :: e_mode(2), e_ray(2)
! Update the inside/outside flag
iop(i) = iop(i) + 1
! Compute B in cartesian coordinates
R = norm2(x(1:2)) * cm
z = x(3) * cm
cosphi = x(1)/R * cm
sinphi = x(2)/R * cm
call bfield(R, z, B_R, B_z, B_phi)
B(1) = B_R*cosphi - B_phi*sinphi
B(2) = B_R*sinphi + B_phi*cosphi
B(3) = B_z
! Get the polarisation vector of the given mode
call pol_limit(N, B, Bres, sox, e_mode(1), e_mode(2))
if(i == 1) then
! For the central ray, compute the polarization ellipse
call field_to_ellipse(e_mode(1), e_mode(2), psi, chi)
else
psi = 0
chi = 0
end if
if (perfect) then
! Ignore the given vector and use the expected one
! Note: this will give 100% coupling to the current mode
ext(i) = e_mode(1)
eyt(i) = e_mode(2)
end if
! Compute the power coupling with the current mode
e_ray = [ext(i), eyt(i)]
c = abs(dot_product(e_mode, e_ray))**2
! Store both O and X couplings, in this order
c = merge(c, 1-c, sox == -1)
cpl = [c, 1-c]
end subroutine plasma_in
subroutine plasma_out(i,xv,anv,bres,sox,iop,ext,eyt) ! ray exits plasma
! arguments
integer, intent(in) :: i ! ray index
real(wp_), dimension(3), intent(in) :: xv,anv
real(wp_), intent(in) :: bres
integer, intent(in) :: sox
integer, dimension(:), intent(inout), pointer :: iop ! in/out plasma flag
complex(wp_), dimension(:), intent(out), pointer :: ext,eyt
! local variables
real(wp_) :: rm,csphi,snphi,bphi,br,bz
real(wp_), dimension(3) :: bv,xmv
!
iop(i)=iop(i)+1 ! in->out
xmv=xv*0.01_wp_ ! convert from cm to m
rm=sqrt(xmv(1)**2+xmv(2)**2)
csphi=xmv(1)/rm
snphi=xmv(2)/rm
call bfield(rm,xmv(3),br,bz,bphi)
bv(1)=br*csphi-bphi*snphi
bv(2)=br*snphi+bphi*csphi
bv(3)=bz
call pol_limit(anv,bv,bres,sox,ext(i),eyt(i)) ! polarization at plasma exit
end subroutine plasma_out
! ------------------------------
! subroutine wall_in(i) ! ray enters vessel
! integer, intent(in) :: i ! ray index
!
! iow(i)=iow(i)+1
! end subroutine wall_in
! ------------------------------
subroutine wall_out(i,ins,xv,anv,bres,sox,psipol1,chipol1,iow,iop,ext,eyt) ! ray exits vessel
! arguments
integer, intent(in) :: i ! ray index
logical, intent(in) :: ins ! inside plasma? (ins=1 plasma/wall overlap)
real(wp_), dimension(3), intent(inout) :: xv,anv
real(wp_), intent(in) :: bres
integer, intent(in) :: sox
real(wp_), intent(out) :: psipol1,chipol1
integer, dimension(:), intent(inout), pointer :: iow,iop ! in/out vessel and plasma flags
complex(wp_), dimension(:), intent(inout), pointer :: ext,eyt
! local variables
integer :: irfl
real(wp_), dimension(3) :: xvrfl,anvrfl,walln
complex(wp_) :: ext1,eyt1
!
iow(i)=iow(i)+1 ! out->in
if(ins) call plasma_out(i,xv,anv,bres,sox,iop,ext,eyt) ! plasma-wall overlapping
call wall_refl(xv-dst*anv,anv,ext(i),eyt(i),xvrfl,anvrfl,ext1,eyt1,walln,irfl) ! ray reflects at wall
ext(i) = ext1 ! save parameters at wall reflection
eyt(i) = eyt1
xv = xvrfl
anv = anvrfl
if(i == 1) then ! polarization angles at wall reflection for central ray
call field_to_ellipse(ext1, eyt1, psipol1, chipol1)
else
psipol1 = zero
chipol1 = zero
end if
end subroutine wall_out
! ------------------------------
subroutine initbeam(i,iroff,iboff,iwait,stv,jphi_beam,pins_beam,currins_beam, &
dpdv_beam,jcd_beam) ! initialization at beam propagation start
use logger, only : log_info, log_warning
! arguments
integer, intent(in) :: i ! beam index
logical, dimension(:,:), intent(in), pointer :: iroff ! global ray status (F = active, T = inactive)
logical, intent(out) :: iboff
logical, dimension(:), intent(out), pointer :: iwait
real(wp_), dimension(:), intent(out), pointer :: jphi_beam,pins_beam, &
currins_beam,dpdv_beam,jcd_beam,stv
character(256) :: msg ! buffer for formatting log messages
iboff = .false. ! beam status (F = active, T = inactive)
iwait = iroff(:,i) ! copy ray status for current beam from global ray status
if(all(iwait)) then ! no rays active => stop beam
iboff = .true.
else if (any(iwait)) then
! only some rays active
write (msg,'(" beam ",g0,": only some rays are active!")') i
call log_warning(msg, mod='multipass', proc='initbeam')
end if
stv = zero ! starting step
jphi_beam = zero ! 1D beam profiles
pins_beam = zero
currins_beam = zero
dpdv_beam = zero
jcd_beam = zero
end subroutine initbeam
! ------------------------------
subroutine initmultipass(i,iox,iroff,yynext,yypnext,yw0,ypw0,stnext,p0ray, &
taus,tau1,etau1,cpls,cpl1,lgcpl1,psipv,chipv) ! initialization before pass loop
! arguments
logical, intent(in) :: i ! ipol
integer, intent(in) :: iox ! mode active on 1st pass
logical, dimension(:,:), intent(out), pointer :: iroff ! global ray status (F = active, T = inactive)
real(wp_), dimension(:), intent(out), pointer :: p0ray,tau1,etau1,cpl1,lgcpl1, &
psipv,chipv
real(wp_), dimension(:,:), intent(out), pointer :: yw0,ypw0,stnext,taus,cpls
real(wp_), dimension(:,:,:), intent(out), pointer :: yynext,yypnext
!
iroff = .false. ! global ray status (F = active, T = inactive)
if(.not. i) call turnoffray(0,1,3-iox,iroff) ! !ipol => stop other mode (iox=1/2 -> stop ib=2/1 at first pass)
yynext = zero ! starting beam coordinates (1)
yypnext = zero ! starting beam coordinates (2)
yw0 = zero ! temporary beam coordinates (1)
ypw0 = zero ! temporary beam coordinates (2)
stnext = zero ! starting beam step
p0ray = zero ! starting beam power
taus = zero ! beam tau from previous passes
tau1 = zero
etau1 = one
cpls = one ! beam coupling from previous passes
cpl1 = one
lgcpl1 = zero
psipv = zero ! psi polarization angle at vacuum-plasma boundary
chipv = zero ! chi polarization angle at vacuum-plasma boundary
end subroutine initmultipass
! ------------------------------
subroutine turnoffray(jk,ip,ib,iroff) ! turn off ray propagation
! arguments
integer, intent(in) :: jk, ip, ib ! ray (0=all rays), pass, beam indexes
logical, dimension(:,:), intent(out), pointer :: iroff ! global ray status (F = active, T = inactive)
! local variables
integer :: ipx, i1, i2
!
if(jk==0) then ! stop all rays
do ipx=ip,ipass ! from pass ip to last pass
i1 = 2**ipx-2+2**(ipx-ip)*(ib-1)+1 ! first derived beam at pass ipx
i2 = 2**ipx-2+2**(ipx-ip)*ib ! last derived beam at pass ipx (i1=i2 for ipx=ip)
iroff(:,i1:i2) = .true.
end do
else ! only stop ray jk
do ipx=ip,ipass
i1 = 2**ipx-2+2**(ipx-ip)*(ib-1)+1
i2 = 2**ipx-2+2**(ipx-ip)*ib
iroff(jk,i1:i2) = .true.
end do
end if
end subroutine turnoffray
! ------------------------------
subroutine alloc_multipass(dim,iwait,iroff,iop,iow,yynext,yypnext,yw0,ypw0,stnext, &
stv,p0ray,taus,tau1,etau1,cpls,cpl1,lgcpl1,jphi_beam, &
pins_beam,currins_beam,dpdv_beam,jcd_beam,psipv,chipv)
integer :: dim
logical, dimension(:), intent(out), pointer :: iwait
logical, dimension(:,:), intent(out), pointer :: iroff
integer, dimension(:), intent(out), pointer :: iop,iow
real(wp_), dimension(:), intent(out), pointer :: jphi_beam,pins_beam,currins_beam, &
dpdv_beam,jcd_beam,stv,tau1,etau1,cpl1,lgcpl1,p0ray,psipv,chipv
real(wp_), dimension(:,:), intent(out), pointer :: taus,cpls,stnext,yw0,ypw0
real(wp_), dimension(:,:,:), intent(out), pointer :: yynext,yypnext
call dealloc_multipass(iwait,iroff,iop,iow,yynext,yypnext,yw0,ypw0,stnext,stv, &
p0ray,taus,tau1,etau1,cpls,cpl1,lgcpl1,jphi_beam,pins_beam,currins_beam, &
dpdv_beam,jcd_beam,psipv,chipv)
nbeam_max = 2**ipass ! max n of beams active at a time
nbeam_tot = 2**(ipass+1)-2 ! total n of beams
allocate(iwait(nray),iroff(nray,nbeam_tot),iop(nray),iow(nray), &
yynext(6,nray,nbeam_max-2),yypnext(6,nray,nbeam_max-2), &
yw0(6,nray),ypw0(6,nray),stnext(nray,nbeam_tot),stv(nray), &
p0ray(nray),taus(nray,nbeam_tot),tau1(nray),etau1(nray), &
cpls(nray,nbeam_tot),cpl1(nray),lgcpl1(nray),jphi_beam(dim), &
pins_beam(dim),currins_beam(dim),dpdv_beam(dim),jcd_beam(dim), &
psipv(0:nbeam_tot),chipv(0:nbeam_tot))
end subroutine alloc_multipass
! ------------------------------
subroutine dealloc_multipass(iwait,iroff,iop,iow,yynext,yypnext,yw0,ypw0,stnext, &
stv,p0ray,taus,tau1,etau1,cpls,cpl1,lgcpl1,jphi_beam, &
pins_beam,currins_beam,dpdv_beam,jcd_beam,psipv,chipv)
logical, dimension(:), intent(out), pointer :: iwait
logical, dimension(:,:), intent(out), pointer :: iroff
integer, dimension(:), intent(out), pointer :: iop,iow
real(wp_), dimension(:), intent(out), pointer :: stv,p0ray,tau1,etau1,cpl1,lgcpl1, &
jphi_beam,pins_beam,currins_beam,dpdv_beam,jcd_beam,psipv,chipv
real(wp_), dimension(:,:), intent(out), pointer :: yw0,ypw0,stnext,taus,cpls
real(wp_), dimension(:,:,:), intent(out), pointer :: yynext,yypnext
if (associated(iwait)) deallocate(iwait)
if (associated(iroff)) deallocate(iroff)
if (associated(iop)) deallocate(iop)
if (associated(iow)) deallocate(iow)
if (associated(yynext)) deallocate(yynext)
if (associated(yypnext)) deallocate(yypnext)
if (associated(yw0)) deallocate(yw0)
if (associated(ypw0)) deallocate(ypw0)
if (associated(stnext)) deallocate(stnext)
if (associated(stv)) deallocate(stv)
if (associated(p0ray)) deallocate(p0ray)
if (associated(taus)) deallocate(taus)
if (associated(tau1)) deallocate(tau1)
if (associated(etau1)) deallocate(etau1)
if (associated(cpls)) deallocate(cpls)
if (associated(cpl1)) deallocate(cpl1)
if (associated(lgcpl1)) deallocate(lgcpl1)
if (associated(jphi_beam)) deallocate(jphi_beam)
if (associated(pins_beam)) deallocate(pins_beam)
if (associated(currins_beam)) deallocate(currins_beam)
if (associated(dpdv_beam)) deallocate(dpdv_beam)
if (associated(jcd_beam)) deallocate(jcd_beam)
if (associated(psipv)) deallocate(psipv)
if (associated(chipv)) deallocate(chipv)
end subroutine dealloc_multipass
end module multipass