GFWIGGLER—Tracks through a wiggler using generate function method of J. Bahrdt and G. Wuestefeld (BESSY, Berlin, Germany).

Tracks through a wiggler using generate function method of J. Bahrdt and G. Wuestefeld (BESSY, Berlin, Germany).
Parallel capable? : yes
GPU capable? : no
Back-tracking capable? : no


Parameter Name	Units	Type	Default	Description

L	M	double	0.0	Total length

B_MAX	T	double	0.0	Maximum on-axis magnetic field at gap=GAP0 and equal longitudinal phases of PHASE_1,2,3,4

SHIM_SCALE		double	1	Scaling factor of shim correction field.

DX	M	double	0.0	Misaligment.

DY	M	double	0.0	Misaligment.

DZ	M	double	0.0	Misaligment.

TILT	RAD	double	0.0	Rotation about beam axis.

PERIODS		long	0	Total number of wiggler periods. Include end poles

STEP		long	1	Number of normal periods to track for each step

ORDER		short	0	Order=3 including the 3rd order terms. Otherwise using 2nd order formula.

END_POLE		short	1	The ending poles are treated as 2 half periods at each sides of the wiggler with reducing field strength, such as 0.25, -0.75, ..., 0.75, -0.25. Periods has to > 2

SHIM_ON		short	0	Include shim correction

INPUT_FILE		STRING	NULL	Name of SDDS file with By harmonic data given at GAP0 and equal longitudinal phases.

SHIM_INPUT		STRING	NULL	Name of SDDS file with shim field integral harmonic data given at GAP0.

SYNCH_RAD		short	0	Include classical, single-particle synchrotron radiation?

ISR		short	0	Include incoherent synchrotron radiation (quantum excitation)?

Tracks through a wiggler using generate function method of J. Bahrdt and G. Wuestefeld (BESSY, Berlin, Germany).


Parameter Name	Units	Type	Default	Description

ISR1PART		short	1	Include ISR for single-particle beam only if ISR=1 and ISR1PART=1

X0	M	double	0.0	Offset of magnet row center in meter.

GAP0	M	double	0.0	Nominal magnetic gap.

D_GAP	M	double	0.0	Delta gap: actual gap - nominal gap

PHASE_1	RAD	double	0.0	Longitudinal phase of the first row (top right)

PHASE_2	RAD	double	0.0	Longitudinal phase of the second row (top left)

PHASE_3	RAD	double	0.0	Longitudinal phase of the third row (bottom left)

PHASE_4	RAD	double	0.0	Longitudinal phase of the fourth row (bottom right)

VERBOSITY		short	0	A higher value requires more detailed printouts related to computations.

GROUP		string	NULL	Optionally used to assign an element to a group, with a user-defined name. Group names will appear in the parameter output file in the column ElementGroup

N.B.: at present this element is not included in computations of beam moments (moments_output command).

This element simulates a wiggler or undulator using the generate function method given by J. Bahrdt and G. Wüstefeld (“Symplectic tracking and compensation of dynamic field integrals in complex undulator structures,” PRSTAB 14, 040703, 2011.).

To use the element, one must supply an SDDS file giving harmonic analysis of the wiggler field. The field expansion used by the code is for a wiggler working at the nominal gap and provide pure horizontal deflecting to the on-axis beam. See CWIGGLER, horizontal wiggler with normal poles, for detail explaination of the field expansion and format of the input file. Besides the required columns of Cmn, KxOverKw, KyOverKw, and KzOverKw by the CWIGGLER elements, two more input columns are needed:

If a file include all required columns from CWIGGLER and GFWIGGLER then user can use either of the both methods for simulating a horizontal planar wiggler.

An universal wiggler field, which be used for generating an arbitrary polarization, can be derived by given different longitudinal phase parameters: PHASE_1,2,3,4. The photon energy can be varied by a non-zero D_GAP value.

10.40 GFWIGGLER—Tracks through a wiggler using generate function method of J. Bahrdt and G. Wuestefeld (BESSY, Berlin, Germany).