|BIN_SIZE||double||0.0||bin size for current histogram (use 0 for autosize)|
|N_BINS||long||20||number of bins for current histogram|
||don't affect the beam until this pass|
||use "Symm" columns from URMEL output file?|
|FACTOR||double||1||factor by which to multiply shunt impedances|
|CUTOFF||double||0.0||If 0, cutoff frequency. Modes above this frequency are ignored.|
|OUTPUT_FILE||STRING||NULL||Output file for voltage in each mode.|
|FLUSH_INTERVAL||long||1||Interval in passes at which to flush output data.|
||Number of passes over which to linearly ramp up the impedance to full strength.|
|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 is similar to RFMODE, but it allows faster simulation of more than one mode. Also, the mode data is specified in an SDDS file. This file can be generated using the APS version of URMEL, or by hand. It must have the following columns and units:
USE_SYMM_DATAis non-zero, then ShuntImpedanceSymm is used. The latter is the full-cavity shunt impedance that URMEL computes by assuming that the input cavity used is one half of a symmetric cavity.
The file may also have the following column:
In many simulations, a transient effect may occur when using this element because, in the context of the simulation, the impedance is switched on instantaneously. This can give a false indication of the threshold for instability. The RAMP_PASSES parameter should be used to prevent this by slowly ramping the impedance to full strength. This idea is from M. Blaskiewicz (BNL).