10.111 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∕mdouble 0.0

shunt impedance, Ra=Vˆ
2  /P






RS Ohm∕mdouble 0.0

shunt impedance (Rs=Ra/2)






Q double 0.0

cavity Q






FREQ Hz double 0.0

frequency






CHARGE C double 0.0

beam charge (or use CHARGE element)






BETA double 0.0

normalized load impedance






BIN_SIZE S double 0.0

bin size for current histogram (use 0 for autosize)






N_BINS long 20

number of bins for current histogram






INTERPOLATE long 0

if non-zero, interpolate voltage within bins






PLANE STRINGboth

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 STRINGNULL

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.






TRFMODE continued

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






Parameter Name UnitsType 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 stringNULL

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.

TRWAKE