gray/doc/man/gray.ini.5.md

title	section
GRAY.INI	5

NAME

gray.ini --- Configuration file for gray(1)

CONFIGURATION

The configuration file is written in the INI format. The basic syntax is:

[group]
; comment
parameter = value

Group is one of: raytracing, ecrh_cd, antenna, equilibrium, profiles, misc.

Values are valid Fortran values, including numbers (integers or floating points), strings (enclosed in quotes), booleans (.true., .false.) and named constants (e.g. MODE_X).

PARAMETERS

Valid configuration parameters listed by group

Note: parameters with a default value are optional and can be omitted.

raytracing

Raytracing parameters

nrayr

Number of rays in the radial direction

nrayth

Number of rays in the angular direction

rwmax (default: 1.0)

Normalized maximum radius of the beam power

igrad (default: 0)

Switch between simple raytracing (0) and beamtracing (1)

ipass (default: 1)

Max number of crossing (out, in, out) of the plasma. When positive reflections occur on the plasma limiter provided by the G-EQDSK file; when negative on a simple limiter at R=rwall, see below.

ipol (default: .false.)

Whether to compute the wave polarisation from chi, psi (see below)

dst

Step size (cm) for the numerical integration

nstep (default: 12000)

Max number of integration steps

idst (default: STEP_TIME)

Choice of the integration variable. One of:

• STEP_ARCLEN, arc length (s)
• STEP_TIME, time (actually c⋅t)
• STEP_PHASE, phase (actually the real part of the eikonal S_r=k₀⋅φ)

ecrh_cd

ECRH and current drive parameters

iwarm (default: ABSORP_FULL)

Choice of the power absorption model. One of:

• ABSORP_OFF, no absorption at all
• ABSORP_WEAK, weakly relativistic
• ABSORP_FULL, fully relativistic (faster variant)
• ABSORP_FULL_ALT, fully relativistic (slower variant)

Note: iwarm /= ABSORP_OFF is required for current drive.

ilarm (default: 5)

Order of the electron Larmor radius expansion (used by some absorption models)

imx (default: -20)

Max number of iterations for the solution of the dispersion relation (used by some absorption models)

Note: if negative the result of the first iteration will be used in case the result doesn't converge within |imx| iterations.

ieccd (default: CD_NEOCLASSIC)

Current drive model. One of:

• CD_OFF, no current drive at all
• CD_COHEN, Cohen
• CD_NO_TRAP, no trapping
• CD_NEOCLASSIC, Neoclassical

antenna

Antenna/beam launcher parameters

alpha

Poloidal launch angle (deg). Positive is down

beta

Toroidal launch angle (deg). Positive is right

power (default: 1.0)

Injected power (MW)

iox

Polarisation mode. One of:

• MODE_O, ordinary (O)
• MODE_X, extraordinary (X)

psi (default: 0.0)

ψ (deg), angle between the x and the major axis of the polarisation ellipse. ψ∈[-90, 90] and is positive for rotating counterclockwise.

Note: only used in alternative to iox if ipol=.true..

chi (default: 0.0)

χ (deg), angle between the principal axes of the polarisation ellipse. χ∈[-45, 45] and is defined by tan(χ) = b/a, where a,b are the major,minor semi-axis, respective.

χ>0 means the ellipse is traced clockwise in the x∧y plane with the z axis in the direction of the wave propagation. In other words: negative helicity (projection of spin angular momentum unto wavevector) or left handed wave (IEEE convention).

Note: only used in alternative to iox if ipol=.true..

ibeam (default: BEAM_0D)

Beam parameters file format. One of:

• BEAM_0D, fixed beam parameters
• BEAM_1D, 1D steering angle table
• BEAM_2D, 2D steering angles table

filenm

Filepath of the beam data (relative to the gray.ini file)

equilibrium

MHD equilibrium parameters

iequil (default: EQ_EQDSK_FULL)

MHD equilibrium kind. One of:

• EQ_VACUUM, vacuum (i.e. no plasma at all)
• EQ_ANALYTICAL, analytical model
• EQ_EQDSK_FULL, G-EQDSK format - data valid on the whole domain
• EQ_EQDSK_PARTIAL, G-EQDSK format - data valid only inside the LCFS

filenm

Filepath of the equilibrium data (relative to the gray.ini file)

icocos (default: 3)

COCOS index of the equilibrium data (G-EQDSK only)

ipsinorm (default: .false.)

Whether the poloidal function is normalised (G-EQDSK only)

Note: Normalised means ψ(axis)=0, ψ(boundary)=1

idesc (default: .true.)

Whether the header starts with a description, a.k.a identification string (G-EQDSK only)

ifreefmt (default: .false.)

Whether the records have variable length (G-EQDSK only)

Note: some non-compliant programs output numbers formatted with variable length instead of using the single (5e16.9) specifier.

ixp (default: X_IS_MISSING)

Position of the X point. One of:

• X_IS_MISSING, No X point
• X_AT_TOP, At the top of the plasma
• X_AT_BOTTOM, At the bottom of the plasma

ssplps (default: 0.005)

Tension for the ψ_n(R,Z) spline, normalised poloidal flux

Note: 0 means perfect interpolation

ssplf (default: 0.01)

Tension for the F(ψ)=R⋅B_T spline, poloidal current function

Note: 0 means perfect interpolation

sgnb (default: 0)

Force the sign of the toroidal field. One of:

• +1, counter-clockwise (viewed from above)
• -1, clockwise
• 0, use sign from COCOS

sgni (default: 0)

Force the sign of the plasma current. One of: +1,

• +1, counter-clockwise (viewed from above)
• -1, clockwise
• 0, use sign from COCOS

factb (default: 1.0)

Rescaling factor for the magnetic field

profiles

(input) plasma profiles parameters

iprof

Plasma profiles kind. One of:

• PROF_ANALYTIC, analytical model
• PROF_NUMERIC, numerical data (ρ, n_e, T_e, table)

irho

Plasma profiles radial coordinate. One of:

• RHO_TOR, ρ_t = √Φ (where Φ is the normalised toroidal flux)
• RHO_POL, ρ_p = √ψ (where ψ is the normalised poloidal flux)
• RHO_PSI, normalised poloidal flux ψ

filenm

Filepath of the plasma profiles data (relative to the gray.ini file)

sspld (default: 0.1)

Tension of the electron density spline

Note: 0 means perfect interpolation

factte (default: 1.0)

Rescaling factor for the electron temperature factte = 1

factne (default: 1.0)

Rescaling factor for the density temperature

iscal (default: SCALE_OFF)

Choice of model for rescaling the temperature, density with the magnetic field (if factb ≠ 0 only). One of:

• SCALE_OFF, don't rescale at all
• SCALE_COLLISION, scale while preserving collisionality
• SCALE_GREENWALD, scale while preserving the Greenwald fraction

output

Output data parameters

ipec (default: RHO_TOR)

ECRH&CD profiles grid: Radial coordinate of the uniform grid. One of:

• RHO_TOR, ρ_t = √Φ (where Φ is the normalised toroidal flux)
• RHO_POL, ρ_p = √ψ (where ψ is the normalised poloidal flux)

nrho (default: 501)

Number of in the radial grid

istpr (default: 5)

Subsampling factors for the beam cross section (units 8, 12)

istpl (default: 5)

Subsampling factors for the outer rays data (unit 33)

misc

Other parameters

rwall

Radius of the inner wall (m). Used to build a simple limiter for reflections (only when ipass<0)

EXAMPLE

Below is an example of a gray.ini file

[raytracing]
; beamtracing with 16×24 rays
nrayr = 16
nrayth = 24
igrad = 1
; integrate in the phase
dst = 0.05
nstep = 2400
idst = STEP_PHASE

[antenna]
; vertical launch
alpha = 89.45
beta = 0.0
iox = MODE_X
ibeam = BEAM_1D
filenm = "beamdata.txt"

[equilibrium]
filenm = "equilibrium.eqdsk"
icocos = 2

[profiles]
; analytical profiles
iprof = PROF_ANALYTIC
irho = RHO_TOR
filenm = "profiles.txt"
sspld = 0.01

[output]
ipec = RHO_POL
nrho = 1001

[misc]
rwall = 0.6

SEE ALSO

gray(1), beamdata.txt(5), profiles.txt(5), magneticdata.txt(5)