TRFMODE—A simulation of a beam-driven TM dipole mode of an RF cavity.

A simulation of a beam-driven TM dipole mode of an RF cavity.
Parallel capable? : yes
GPU capable? : no
Back-tracking capable? : no


Parameter Name	Units	Type	Default	Description

RA	Ohm∕m	double	0.0	shunt impedance, Ra=V/P

RS	Ohm∕m	double	0.0	shunt impedance (Rs=Ra/2)

Q		double	0.0	cavity Q

FREQ	Hz	double	0.0	frequency

CHARGE	C	double	0.0	Deprecated—use CHARGE element

BETA		double	0.0	normalized load impedance

BIN_SIZE	S	double	0.0	bin size for current histogram

N_BINS		long	20	number of bins for current histogram

INTERPOLATE		long	0	if non-zero, interpolate voltage within bins

PLANE		STRING	both	x, y, or both

SAMPLE_INTERVAL		long	1	passes between output to RECORD file

PER_PARTICLE_OUTPUT		long	0	If non-zero, then in BINLESS mode, provides per-particle output of RECORD data.

RECORD		STRING	NULL	output file for cavity data

SINGLE_PASS		long	0	if nonzero, don’t accumulate field from pass to pass

RIGID_UNTIL_PASS		long	0	don’t affect the beam until this pass

DX	M	double	0.0	misalignment

DY	M	double	0.0	misalignment

XFACTOR		double	1	factor by which to multiply shunt impedances

YFACTOR		double	1	factor by which to multiply shunt impedances

RAMP_PASSES		long	0	Number of passes over which to linearly ramp up the impedance to full strength.

BINLESS		long	0	If nonzero, use algorithm that doesn’t requiring binning. Best for few particles, widely spaced.


Parameter Name	Units	Type	Default	Description

RESET_FOR_EACH_STEP		long	1	If nonzero, voltage and phase are reset for each simulation step.

LONG_RANGE_ONLY		long	0	If nonzero, induced voltage from present turn does not affect bunch. Short range wake should be included via TRWAKE or ZTRANSVERSE element.

N_CAVITIES		long	1	effect is multiplied by this number, simulating N identical cavities

BUNCHED_BEAM_MODE		long	1	If non-zero, then do calculations bunch-by-bunch.

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

This element simulates a beam-driven dipole mode cavity using the fundamental theorem of beam loading and phasor rotation.

Normally, the field dumped in the cavity by one particle affects trailing particles in the same turn. However, if one is also using a TRWAKE or ZTRANSVSE element to simulate the short-range wake of the cavity, this would be double-counting. In that case, one can use LONG_RANGE_ONLY=1 to suppress the same-turn effects of the RFMODE element.

10.116 TRFMODE—A simulation of a beam-driven TM dipole mode of an RF cavity.