The physical parameters of the Neutrals model.
| Name | Default value | Valid values | Complexity level | Description |
|---|---|---|---|---|
ne_ref |
NaN |
> 0.0 |
beginner | Reference plasma density in Braginskii model [cm ^-3] (see TODO). |
te_ref |
NaN |
> 0.0 |
beginner | Reference temperature in Braginskii model [eV] (see TODO). |
k_ref |
NaN |
>= 0.0 |
beginner | Reference rate coefficient [cm^3/s] (see TODO). |
w_ref |
NaN |
>= 0.0 |
beginner | Reference cooling rate coefficient [eV cm^3/s] (see TODO). |
s_cx |
NaN |
>= 0.0 |
beginner | Normalized charge exchange cross section (see TODO). |
mach_limit |
1,0 |
any real | medium | Mach limit, for limiting diffusion coefficient value upwards. Negative values correspond to no limiter (see TODO). |
pot_iz |
13.6 |
> 0.0 |
beginner | Ionization potential [eV] (see TODO). |
pardiss_coeff_dens |
0.0 |
>= 0.0 |
medium | Parallel (numerical) diffusion coefficent acting on neutrals density (see TODO). |
pardiss_coeff_parmom |
0.0 |
>= 0.0 |
medium | Parallel (numerical) diffusion coefficent acting on neutrals parallel momentum (see TODO). |
pardiss_coeff_pressure |
0.0 |
>= 0.0 |
medium | Parallel (numerical) diffusion coefficent acting on neutrals pressure (see TODO). |
rcy_coeff |
0.0 |
>= 0.0, <= 1.0 |
medium | Recycling coefficient for fluxes hitting domain boundaries (see TODO). |
evolve_pressure |
T |
(F,T) |
medium | Whether or not to evolve the third neutrals moment (neutrals pressure). If not, neutrals take ion temperature instead. |
apply_neumann_mirror |
F |
(F,T) |
expert | Whether or not to apply neumann mirroring, i.e. to apply perpendicular neumann boundary conditions at penalisation entrance. To be used when running with recycling boundary conditions. Requires all parameters in &neut_boundaries_perp to be set to BND_TYPE_DIRICHLET_ZERO. |
gas_puff_on |
F |
(F,T) |
expert | Whether or not to apply gas puffing (additional gaussian sources in neutral density equation.) |
gas_puff_path |
'.in' |
String | expert | Path to file where gas puffing source parameters are specified. |
diff_tn_min |
0.0 |
>= 0.0 |
expert | Effectively sets a lower bound on the pressure diffusion coefficient by ampliyfying the standard coefficient by a factor max(1, diff_tn_min / T_N). |
src_rcy_temp |
0.0 |
>= 0.0 |
expert | When using recycling sources, sets the temperature of the newly generated recycled neutral particles. By default, it is zero, meaning no net neutrals pressure is created. |
cx_cooling_thresh |
0.0 |
>= 0.0 |
expert | If neutrals temperature falls below this value, the CX-equilibration term in the ion temperature will treat neutrals as having zero temperature, providing stronger-than-normal ion cooling. By default, it is disabled. NOTE: This feature breaks energy conservation! |
cx_cooling_thresh_min |
0.0 |
>= 0.0, < cx_cooling_thresh |
expert | Only to be used together with cx_cooling_thresh > 0. Sets the minimum neutrals temperature, below which the neutrals temperature is no longer set to zero, stopping the application of cx_cooling_thresh. |
diff_co_smoothing |
0.0 |
>= 0.0 |
expert | Smoothens CX diffusivity by appling perpendicular diffusion on it, with diffusion coefficient diff_co_smoothing (disabled for 0.0). Helps improve numeric stability in detached cases with steep gradients in CX diffusivity. |
Floors are present to avoid density to become zero or negative.
| Name | Default value | Valid values | Complexity level | Description |
|---|---|---|---|---|
floor_dens |
EPS |
real | beginner | Minumum allowed neutral density. |
floor_temp |
EPS |
any real | medium | Minimal neutrals temperature. If evolve_pressure=F, neutrals have ion temperature above this minimum. |
rho_min_for_parmom_advection |
-LARGE |
real | medium | Flux surface below which certain right-hand-side terms are set to zero to avoid numerical problems due to divisions by small numbers (where neutrals density is near zero). |
Switches for each individual term of the Neutrals model. This is an exhaustive list and for the individual parameters and default values the reader is referred to the corresponding source code file params_neutrals_switches_m.f90.
Parameters for perpendicular boundary conditions of neutral fields.
| Name | Default value | Valid values | Complexity level | Description |
|---|---|---|---|---|
bndtype_neut_<dens,parmom,pressure>_<core,wall,dome,out> |
'BND_TYPE_DIRICHLET_ZERO' |
('BND_TYPE_DIRICHLET_ZERO', 'BND_TYPE_NEUMANN') |
beginner | Type of boudbary condition at corresponding boundary section for corresponding quantity. |
bndval_neut_dens_<core,wall,dome,out> |
0.0 |
>= 0.0 |
beginner | Value (for BND_TYPE_DIRICHLET_ZERO) or gradient (for BND_TYPE_NEUMANN) at corresponding boundary section for neutrals density. |
bndval_neut_parmom_<core,wall,dome,out> |
0.0 |
any real | beginner | Value (for BND_TYPE_DIRICHLET_ZERO) or gradient (for BND_TYPE_NEUMANN) at corresponding boundary section for neutrals parallel momentum. |
bndval_neut_pressure_<core,wall,dome,out> |
0.0 |
any real | beginner | Value (for BND_TYPE_DIRICHLET_ZERO) or gradient (for BND_TYPE_NEUMANN) at corresponding boundary section for neutrals pressure. |
Parameters for penalisation boundary conditions of neutral fields.
| Name | Default value | Valid values | Complexity level | Description |
|---|---|---|---|---|
bndtype_neut_<dens,parmom,pressure>_pen |
'BND_TYPE_DIRICHLET_ZERO' |
('BND_TYPE_DIRICHLET_ZERO', 'BND_TYPE_NEUMANN') |
beginner | Type of boundary in penalisation region for corresponding quantity. |
bndval_neut_dens_peninto |
1.0 |
> 0 |
beginner | Value of neutrals density in penalisation region, where magnetic field is directed into boundary. Only for pen_bndtype_neutrals_dens='BND_TYPE_DIRICHLET_ZERO'. |
bndval_neut_dens_penout |
1.0 |
> 0 |
beginner | Value of neutrals density in penalisation region, where magnetic field is directed out of boundary. Only for pen_bndtype_neutrals_dens='BND_TYPE_DIRICHLET_ZERO'. |
bndval_neut_dens_peninto_second |
1.0 |
> 0 |
medium | Value of neutrals density in the second penalisation region in double-null equilibrium, where magnetic field is directed into boundary. Only for pen_bndtype_neutrals_dens='BND_TYPE_DIRICHLET_ZERO'. |
bndval_neut_dens_penout_second |
1.0 |
> 0 |
medium | Value of neutrals density in the second penalisation region in double-null equilibrium, where magnetic field is directed out of boundary. Only for pen_bndtype_neutrals_dens='BND_TYPE_DIRICHLET_ZERO'. |
| bndval_neut_parmom_peninto | 0.0 | any real | beginner | Value of neutrals parallel momentum in penalisation region, where magnetic field is directed into boundary. Only for pen_bndtype_neutrals_parmom='BND_TYPE_DIRICHLET_ZERO'. |
| bndval_neut_parmom_penout | 0.0 | any real | beginner | Value of neutrals parallel momentum in penalisation region, where magnetic field is directed out of boundary. Only for pen_bndtype_neutrals_parmom='BND_TYPE_DIRICHLET_ZERO'. |
| bndval_neut_parmom_peninto_second | 0.0 | any real | medium | Value of neutrals parallel momentum in the second penalisation region in double-null equilibrium, where magnetic field is directed into boundary. Only for pen_bndtype_neutrals_parmom='BND_TYPE_DIRICHLET_ZERO'. |
| bndval_neut_parmom_penout_second | 0.0 | any real | medium | Value of neutrals parallel momentum in the second penalisation region in double-null equilibrium, where magnetic field is directed out of boundary. Only for pen_bndtype_neutrals_parmom='BND_TYPE_DIRICHLET_ZERO'. |
| bndval_neut_pressure_peninto | 1.0 |> 0 | beginner | Value of neutrals pressure in penalisation region, where magnetic field is directed into boundary. Only for pen_bndtype_neutrals_pressure='BND_TYPE_DIRICHLET_ZERO'. |
| bndval_neut_pressure_penout | 1.0 |> 0 | beginner | Value of neutrals pressure in penalisation region, where magnetic field is directed out of boundary. Only for pen_bndtype_neutrals_pressure='BND_TYPE_DIRICHLET_ZERO'. |
| bndval_neut_pressure_peninto_second | 1.0 |> 0 | medium | Value of neutrals pressure in the second penalisation region in double-null equilibrium, where magnetic field is directed into boundary. Only for pen_bndtype_neutrals_pressure='BND_TYPE_DIRICHLET_ZERO'. |
| bndval_neut_pressure_penout_second | 1.0 |> 0 | medium | Value of neutrals pressure in the second penalisation region in double-null equilibrium, where magnetic field is directed out of boundary. Only for pen_bndtype_neutrals_pressure='BND_TYPE_DIRICHLET_ZERO'. |
| second_pen_flag | 0 |(0, 1, -1) | medium | second_pen_flag=0, do not distinguish the second penalisation boundary; second_pen_flag=1, distinguish the second penalisation by y-y0>0; second_pen_flag=-1, distinguish the second penalisation by y-y0<0, where y0 is the y value of magnetic axis. (N.B. y coordinator may have been flipped) |
| on_neutrals_temp | F | (F,T) | medium | Whether or not to apply neutrals pressure boundary conditions on neutrals temperature instead. |
Filepaths to neutrals data for rate coefficients.
| Name | Default value | Valid values | Complexity level | Description |
|---|---|---|---|---|
path_k_iz |
'S_H.dat' |
String of maxlen=1024 | medium | Filepath to ionization rate data (see TODO). |
path_k_rec |
'R_H.dat' |
String of maxlen=1024 | medium | Filepath to reconmbination rate data (see TODO). |
path_w_iz |
'Wiz_H.dat' |
String of maxlen=1024 | medium | Filepath to ionization cooling rate data (see TODO). |
path_p_rec |
'Pradrec_H.dat' |
String of maxlen=1024 | medium | Filepath to recombination cooling rate data (see TODO). |
Parameters for selection of initial state for neutral fields.
| Name | Default value | Valid values | Complexity level | Description |
|---|---|---|---|---|
neut_iselect |
'NONE' |
('CONTINUE', 'HOMOGENEOUS', 'MMS') |
beginner | Type of initial state fort neutral fields. |
Parameters for coronal impurity model.
| Name | Default value | Valid values | Complexity level | Description |
|---|---|---|---|---|
impy_coronal |
-1.0 |
any real | medium | Impurity concentration (fraction of electron density) [m ^-3]. Negative values disable this feature (see TODO). |
impy_path |
'coronal_nitrogen' |
String of maxlen=1024 | medium | Filepath to radiation rate coefficient table. |
impy_tab_length |
121 |
> 0 |
medium | Number of data points in the table. |