3D magnetic field with tricubic spline interpolation More...

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "../ascot5.h"
#include "../error.h"
#include "../print.h"
#include "B_3DS.h"
#include "../spline/interp.h"

Functions
int	B_3DS_init_offload (B_3DS_offload_data offload_data, real *offload_array)
	Initialize magnetic field offload data.

void	B_3DS_free_offload (B_3DS_offload_data offload_data, real *offload_array)
	Free offload array.

void	B_3DS_init (B_3DS_data Bdata, B_3DS_offload_data offload_data, real *offload_array)
	Initialize magnetic field data struct on target.

a5err	B_3DS_eval_psi (real psi, real r, real phi, real z, B_3DS_data Bdata)
	Evaluate poloidal flux psi.

a5err	B_3DS_eval_psi_dpsi (real psi_dpsi[4], real r, real phi, real z, B_3DS_data *Bdata)
	Evaluate poloidal flux psi and its derivatives.

a5err	B_3DS_eval_rho_drho (real rho_drho[4], real r, real phi, real z, B_3DS_data *Bdata)
	Evaluate normalized poloidal flux rho and its derivatives.

a5err	B_3DS_eval_B (real B[3], real r, real phi, real z, B_3DS_data *Bdata)
	Evaluate magnetic field.

a5err	B_3DS_eval_B_dB (real B_dB[12], real r, real phi, real z, B_3DS_data *Bdata)
	Evaluate magnetic field and its derivatives.

a5err	B_3DS_get_axis_rz (real rz[2], B_3DS_data *Bdata)
	Return magnetic axis R-coordinate.

Detailed Description

3D magnetic field with tricubic 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. However, $B_R$ and $B_z$ components are also evaluated from poloidal magnetic flux $\psi(R,z)$ as

$\begin{align*} B_R &= -\frac{1}{R}\frac{\partial\psi}{\partial z}\\ B_z &= \frac{1}{R}\frac{\partial\psi}{\partial R} \end{align*}$

The total field is then a sum of components interpolated directly from $\mathbf{B}$ and components calculated via interpolated $\psi$ . Note that $\psi$ is assumed to be axisymmetric and is interpolated with bicubic splines. $\psi$ and $\mathbf{B}$ are given in separate grids.

This module does no extrapolation so if queried value is outside the $Rz$ -grid an error is thrown.

The toroidal angle phi is treated as a periodic coordinate meaning that B(phi) = B(phi + N*(b_phimax - b_phimin)) being N the periodic number. Do note that to avoid duplicate data, the last points in phi axis in B data are not at b_phimax, i.e. br[:,-1,:] != BR(phi=b_phimax). It is user's responsibility to provide input whose $\phi$ -grid makes sense (in that it actually represents a periodic field).

See also: B_field.c

Definition in file B_3DS.c.

Function Documentation

◆ B_3DS_init_offload()

int B_3DS_init_offload	(	B_3DS_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_3DS_offload_data.offload_array_length is set here.

The offload array must contain the following data:

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

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 93 of file B_3DS.c.

◆ B_3DS_free_offload()

void B_3DS_free_offload	(	B_3DS_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 202 of file B_3DS.c.

◆ B_3DS_init()

void B_3DS_init	(	B_3DS_data *	Bdata,
		B_3DS_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 215 of file B_3DS.c.

◆ B_3DS_eval_psi()

a5err B_3DS_eval_psi	(	real *	psi,
		real	r,
		real	phi,
		real	z,
		B_3DS_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 285 of file B_3DS.c.

◆ B_3DS_eval_psi_dpsi()

a5err B_3DS_eval_psi_dpsi	(	real	psi_dpsi[4],
		real	r,
		real	phi,
		real	z,
		B_3DS_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 309 of file B_3DS.c.

◆ B_3DS_eval_rho_drho()

a5err B_3DS_eval_rho_drho	(	real	rho_drho[4],
		real	r,
		real	phi,
		real	z,
		B_3DS_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 340 of file B_3DS.c.

◆ B_3DS_eval_B()

a5err B_3DS_eval_B	(	real	B[3],
		real	r,
		real	phi,
		real	z,
		B_3DS_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 378 of file B_3DS.c.

◆ B_3DS_eval_B_dB()

a5err B_3DS_eval_B_dB	(	real	B_dB[12],
		real	r,
		real	phi,
		real	z,
		B_3DS_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 425 of file B_3DS.c.

◆ B_3DS_get_axis_rz()

a5err B_3DS_get_axis_rz	(	real	rz[2],
		B_3DS_data *	Bdata )

Return magnetic axis R-coordinate.

Parameters

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

Returns: Zero a5err value as this function can't fail.

Definition at line 489 of file B_3DS.c.

Functions

Detailed Description

Function Documentation

◆ B_3DS_init_offload()

◆ B_3DS_free_offload()

◆ B_3DS_init()

◆ B_3DS_eval_psi()

◆ B_3DS_eval_psi_dpsi()

◆ B_3DS_eval_rho_drho()

◆ B_3DS_eval_B()

◆ B_3DS_eval_B_dB()

◆ B_3DS_get_axis_rz()