11  Field Output Commands

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There are two routines that can be used to write out the external field used in OPAL-CYCL:

  • DUMPFIELDS: write out a static magnetic field map on a Cartesian grid
  • DUMPEMFIELDS: write out an electromagnetic field map on a 4D grid in space-time; Cartesian and cylindrical grids are supported

DUMPEMFIELDS is an extension of DUMPFIELDS.

OPALX currently supports a single field-output command:

  • DUMPEMFIELDS: write out the external electromagnetic field on a 4D grid in space-time; Cartesian and cylindrical grids are supported

11.1 DUMPFIELDS Command

DUMPFIELDS writes the static magnetic field on a 3D Cartesian grid. The file format is:

<number of rows>
1 x [m]
2 y [m]
3 z [m]
4 Bx [kGauss]
5 By [kGauss]
6 Bz [kGauss]
0
<x0> <y0> <z0> <Bx0> <By0> <Bz0>
<x1> <y1> <z1> <Bx1> <By1> <Bz1>
...

Attributes:

Attribute Meaning
FILE_NAME output file name; existing files are overwritten
X_START, Y_START, Z_START grid origin in m
DX, DY, DZ grid spacing in m
X_STEPS, Y_STEPS, Z_STEPS number of steps; must be positive integers

Example:

DUMPFIELDS, X_START=0., X_STEPS=101, DX=0.100,
            Y_START=0., Y_STEPS=101, DY=0.100,
            Z_START=0., Z_STEPS=1, DZ=0.100,
            FILE_NAME="FieldMapXY.dat";

This writes a mid-plane map in the x-y plane, starting at (0,0) with 101 x 101 samples and z = 0.

11.2 DUMPEMFIELDS Command

DUMPEMFIELDS writes electromagnetic field data on a 4D grid. Two coordinate systems are supported:

  • Cartesian: (x, y, z, t)
  • cylindrical about the z axis: (r, phi, z, t) in OPAL, (r, phi, y, t) in OPALX

11.2.1 Cartesian Mode

Cartesian mode is selected with COORDINATE_SYSTEM = CARTESIAN.

The file format is:

<number of rows>
1  x [m]
2  y [m]
3  z [m]
4  t [ns]
5  Bx [kGauss]
6  By [kGauss]
7  Bz [kGauss]
8  Ex [MV/m]
9  Ey [MV/m]
10 Ez [MV/m]
0
<x0> <y0> <z0> <t0> <Bx0> <By0> <Bz0> <Ex0> <Ey0> <Ez0>
...

The file format is:

<number of rows>
1  x [m]
2  y [m]
3  z [m]
4  t [ns]
5  Bx [T]
6  By [T]
7  Bz [T]
8  Ex [MV/m]
9  Ey [MV/m]
10 Ez [MV/m]
0
<x0> <y0> <z0> <t0> <Bx0> <By0> <Bz0> <Ex0> <Ey0> <Ez0>
...

Attributes in Cartesian mode:

Attribute Meaning
FILE_NAME output file name; existing files are overwritten
COORDINATE_SYSTEM must be CARTESIAN
X_START, Y_START, Z_START grid origin in m
DX, DY, DZ spatial step size in m
X_STEPS, Y_STEPS, Z_STEPS spatial step counts; must be positive integers
T_START start time in ns
DT time step size in ns
T_STEPS number of time steps; must be a positive integer

11.2.2 Cylindrical Mode

Cylindrical mode is selected with COORDINATE_SYSTEM = CYLINDRICAL.

The file format is:

<number of rows>
1 r [m]
2 phi [deg]
3 z [m]
4 t [ns]
5 Br   [kGauss]
6 Bphi [kGauss]
7 Bz   [kGauss]
8 Er   [MV/m]
9 Ephi [MV/m]
10 Ez  [MV/m]
0
<r0> <phi0> <z0> <t0> <Br0> <Bphi0> <Bz0> <Er0> <Ephi0> <Ez0>
...

The file format is:

<number of rows>
1 r [m]
2 phi [deg]
3 y [m]
4 t [ns]
5 Br   [T]
6 Bphi [T]
7 By   [T]
8 Er   [MV/m]
9 Ephi [MV/m]
10 Ey  [MV/m]
0
<r0> <phi0> <y0> <t0> <Br0> <Bphi0> <By0> <Er0> <Ephi0> <Ey0>
...

Attributes in cylindrical mode:

Attribute Meaning
FILE_NAME output file name; existing files are overwritten
COORDINATE_SYSTEM must be CYLINDRICAL
R_START radial start point in m
DR radial step size in m
R_STEPS number of radial steps; must be a positive integer
PHI_START start point in phi
DPHI azimuthal step size
PHI_STEPS number of azimuthal steps; must be a positive integer
T_START start time in ns
DT time step size in ns
T_STEPS number of time steps; must be a positive integer

Additional OPAL cylindrical attributes:

Attribute Meaning
Z_START start point in z [m]
DZ step size in z [m]
Z_STEPS number of z steps; must be a positive integer

Additional OPALX cylindrical attributes:

Attribute Meaning
Y_START start point in y [m]
DY step size in y [m]
Y_STEPS number of y steps; must be a positive integer
CYL_ORIGIN_X, CYL_ORIGIN_Y, CYL_ORIGIN_Z optional cylindrical-origin coordinates in m; defaults are 0