Stellarator magnetic field with cubic spline interpolation. More...

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <string.h>
#include "../ascot5.h"
#include "../error.h"
#include "../print.h"
#include "../consts.h"
#include "B_STS.h"
#include "../linint/linint.h"
#include "../spline/interp.h"

Functions
int	B_STS_init_offload (B_STS_offload_data offload_data, real *offload_array)
	Initialize magnetic field offload data.

void	B_STS_free_offload (B_STS_offload_data offload_data, real *offload_array)
	Free offload array.

void	B_STS_init (B_STS_data Bdata, B_STS_offload_data offload_data, real *offload_array)
	Initialize magnetic field data struct on target.

a5err	B_STS_eval_psi (real psi, real r, real phi, real z, B_STS_data Bdata)
	Evaluate poloidal flux psi.

a5err	B_STS_eval_psi_dpsi (real psi_dpsi[4], real r, real phi, real z, B_STS_data *Bdata)
	Evaluate poloidal flux psi and its derivatives.

a5err	B_STS_eval_rho_drho (real rho_drho[4], real r, real phi, real z, B_STS_data *Bdata)
	Evaluate normalized poloidal flux rho and its derivatives.

a5err	B_STS_eval_B (real B[3], real r, real phi, real z, B_STS_data *Bdata)
	Evaluate magnetic field.

a5err	B_STS_eval_B_dB (real B_dB[12], real r, real phi, real z, B_STS_data *Bdata)
	Evaluate magnetic field and its derivatives.

a5err	B_STS_get_axis_rz (real rz[2], B_STS_data *Bdata, real phi)
	Return magnetic axis Rz-coordinates.

Detailed Description

Stellarator magnetic field with cubic spline interpolation.

This module represents a magnetic field where data is given in $R\phi z$ - grid from which it is interpolated with tricubic splines.

The magnetic field is evaluated from magnetic field strength $\mathbf{B}$ which may not be divergence free. The poloidal magnetic flux $\psi$ is interpolated using tricubic splines as well. $\psi$ and $\mathbf{B}$ are given in separate grids.

The magnetic axis location for stellarators varies with the $\phi$ angle and is evaluated using linear interpolation.

This module does no extrapolation so if queried value is outside the $Rz$ -grid an error is thrown. The $\phi$ -grid is assumed to be periodic. Periodic boundary conditions are used but it is user's responsibility to provide input whose $\phi$ -grid makes sense (in that it actually represents a periodic field), i.e., $\phi_\mathrm{max}-\phi_\mathrm{min} = 2\pi/(N+1)$ . However, do note that in this module $\phi_\mathrm{max}$ is not the "last" grid point but the second last, e.g. if $\phi_\mathrm{min}=0$ and $n_\phi = 360$ , then $\phi_\mathrm{max}=359$ if periodicity is $N=0$ .

See also: B_field.c linint1D.c

Definition in file B_STS.c.

Function Documentation

◆ B_STS_init_offload()

int B_STS_init_offload	(	B_STS_offload_data *	offload_data,
		real **	offload_array )

Initialize magnetic field offload data.

This function takes pre-initialized offload data struct and offload array as inputs. The data is used to fill rest of the offload struct and to construct bicubic splines whose coefficients are stored in re-allocated offload array.

The offload data struct must have the following fields initialized:

B_STS_offload_data.offload_array_length is set here.

The offload array must contain the following data:

offload_array[ z*Bn_r*Bn_z + j*Bn_r + i] = B_R(R_i, phi_z, z_j) [T]
offload_array[ Bn_r*Bn_z*Bn_phi + z*Bn_r*Bn_z + j*Bn_r + i] = B_phi(R_i, phi_z, z_j) [T]
offload_array[2*Bn_r*Bn_z*Bn_phi + z*Bn_r*Bn_z + j*Bn_r + i] = B_z(R_i, phi_z, z_j) [T]
offload_array[3*Bn_r*Bn_z*Bn_phi + z*psin_r*psin_z + j*psin_r + i] = psi(R_i, phi_z, z_j) [V*s*m^-1]
offload_array[3*Bn_r*Bn_z*Bn_phi + psin_r*psin_z*psin_phi + z] = axis_R(phi_z) [m]
offload_array[3*Bn_r*Bn_z*Bn_phi + psin_r*psin_z*psin_phi + n_axis + z] = axis_z(phi_z) [m]

Sanity checks are printed if data was initialized succesfully.

Parameters

offload_data	pointer to offload data struct
offload_array	pointer to offload array which is reallocated here

Returns: zero if initialization succeeded

Definition at line 98 of file B_STS.c.

◆ B_STS_free_offload()

void B_STS_free_offload	(	B_STS_offload_data *	offload_data,
		real **	offload_array )

Free offload array.

Parameters

offload_data	pointer to offload data struct
offload_array	pointer to pointer to offload array

Definition at line 225 of file B_STS.c.

◆ B_STS_init()

void B_STS_init	(	B_STS_data *	Bdata,
		B_STS_offload_data *	offload_data,
		real *	offload_array )

Initialize magnetic field data struct on target.

Parameters

Bdata	pointer to data struct on target
offload_data	pointer to offload data struct
offload_array	offload array

Definition at line 237 of file B_STS.c.

◆ B_STS_eval_psi()

a5err B_STS_eval_psi	(	real *	psi,
		real	r,
		real	phi,
		real	z,
		B_STS_data *	Bdata )

Evaluate poloidal flux psi.

Parameters

psi	pointer where psi [Vsm^-1] value will be stored
r	R coordinate [m]
phi	phi coordinate [rad]
z	z coordinate [m]
Bdata	pointer to magnetic field data struct

Returns: Non-zero a5err value if evaluation failed, zero otherwise

Definition at line 322 of file B_STS.c.

◆ B_STS_eval_psi_dpsi()

a5err B_STS_eval_psi_dpsi	(	real	psi_dpsi[4],
		real	r,
		real	phi,
		real	z,
		B_STS_data *	Bdata )

Evaluate poloidal flux psi and its derivatives.

Parameters

psi_dpsi	pointer for storing psi [Vsm^-1] and its derivatives
r	R coordinate [m]
phi	phi coordinate [rad]
z	z coordinate [m]
Bdata	pointer to magnetic field data struct

Returns: Non-zero a5err value if evaluation failed, zero otherwise

Definition at line 354 of file B_STS.c.

◆ B_STS_eval_rho_drho()

a5err B_STS_eval_rho_drho	(	real	rho_drho[4],
		real	r,
		real	phi,
		real	z,
		B_STS_data *	Bdata )

Evaluate normalized poloidal flux rho and its derivatives.

Parameters

rho_drho	pointer where rho and its derivatives will be stored
r	R coordinate [m]
phi	phi coordinate [rad]
z	z coordinate [m]
Bdata	pointer to magnetic field data struct

Returns: Non-zero a5err value if evaluation failed, zero otherwise

Definition at line 396 of file B_STS.c.

◆ B_STS_eval_B()

a5err B_STS_eval_B	(	real	B[3],
		real	r,
		real	phi,
		real	z,
		B_STS_data *	Bdata )

Evaluate magnetic field.

Parameters

B	pointer to array where magnetic field values are stored
r	R coordinate [m]
phi	phi coordinate [deg]
z	z coordinate [m]
Bdata	pointer to magnetic field data struct

Returns: Non-zero a5err value if evaluation failed, zero otherwise

Definition at line 445 of file B_STS.c.

◆ B_STS_eval_B_dB()

a5err B_STS_eval_B_dB	(	real	B_dB[12],
		real	r,
		real	phi,
		real	z,
		B_STS_data *	Bdata )

Evaluate magnetic field and its derivatives.

Parameters

B_dB	pointer to array where the field and its derivatives are stored
r	R coordinate [m]
phi	phi coordinate [deg]
z	z coordinate [m]
Bdata	pointer to magnetic field data struct

Returns: Non-zero a5err value if evaluation failed, zero otherwise

Definition at line 480 of file B_STS.c.

◆ B_STS_get_axis_rz()

a5err B_STS_get_axis_rz	(	real	rz[2],
		B_STS_data *	Bdata,
		real	phi )

Return magnetic axis Rz-coordinates.

Parameters

rz	pointer where axis R and z [m] values will be stored
Bdata	pointer to magnetic field data struct
phi	phi coordinate [deg]

Returns: Non-zero a5err value if evaluation failed, zero otherwise

Definition at line 531 of file B_STS.c.

Functions

Detailed Description

Function Documentation

◆ B_STS_init_offload()

◆ B_STS_free_offload()

◆ B_STS_init()

◆ B_STS_eval_psi()

◆ B_STS_eval_psi_dpsi()

◆ B_STS_eval_rho_drho()

◆ B_STS_eval_B()

◆ B_STS_eval_B_dB()

◆ B_STS_get_axis_rz()