10.83 RFCW—A combination of RFCA, WAKE, TRWAKE, and LSCDRIFT.

A combination of RFCA, WAKE, TRWAKE, and LSCDRIFT.
Parallel capable? : yes
GPU capable? : yes
Back-tracking capable? : yes






Parameter Name UnitsType Default

Description






L M double 0.0

length






CELL_LENGTH M double 0.0

cell length (used to scale wakes, which are assumed to be given for a cell, according to L/CELL_LENGTH)






VOLT V double 0.0

voltage






PHASE DEGdouble 0.0

phase






FREQ Hz double 500000000

frequency






Q double 0.0

cavity Q (for cavity that charges up to voltage from 0)






PHASE_REFERENCE long 0

phase reference number (to link with other time-dependent elements)






CHANGE_P0 long 0

does element change central momentum?






CHANGE_T long 0

see RFCA documentation






FIDUCIAL STRINGNULL

mode for determining fiducial arrival time (light, tmean, first, pmaximum)






END1_FOCUS long 0

include focusing at entrance?






END2_FOCUS long 0

include focusing at exit?






BODY_FOCUS_MODEL STRINGNULL

None (default) or SRS (simplified Rosenzweig/Serafini for standing wave)






N_KICKS long 0

Number of kicks to use for kick method. Set to zero for matrix method.






ZWAKE long 1

If zero, longitudinal wake is turned off.






TRWAKE long 1

If zero, transverse wakes are turned off.






WAKEFILE STRINGNULL

name of file containing Green functions






ZWAKEFILE STRINGNULL

if WAKEFILE=NULL, optional name of file containing longitudinal Green function






RFCW continued

A combination of RFCA, WAKE, TRWAKE, and LSCDRIFT.






Parameter Name UnitsType Default

Description






TRWAKEFILE STRINGNULL

if WAKEFILE=NULL, optional name of file containing transverse Green functions






TCOLUMN STRINGNULL

column containing time data






WXCOLUMN STRINGNULL

column containing x Green function






WYCOLUMN STRINGNULL

column containing y Green function






WZCOLUMN STRINGNULL

column containing longitudinal Green function






N_BINS long 0

number of bins for current histogram






INTERPOLATE long 0

interpolate wake?






SMOOTHING long 0

Use Savitzky-Golay filter to smooth current histogram?






SG_HALFWIDTH long 4

Savitzky-Golay filter half-width for smoothing






SG_ORDER long 1

Savitzky-Golay filter order for smoothing






DX M double 0.0

misalignment






DY M double 0.0

misalignment






T_REFERENCE S double -1

arrival time of reference particle






LINEARIZE long 0

Linearize phase dependence?






LSC long 0

Include longitudinal space-charge impedance?






LSC_BINS long 1024

Number of bins for LSC calculations






LSC_INTERPOLATE long 1

Interpolate computed LSC wake?






LSC_LOW_FREQUENCY_CUTOFF0 double -1

Highest spatial frequency at which low-frequency cutoff filter is zero. If not positive, no low-frequency cutoff filter is applied. Frequency is in units of Nyquist (0.5/binsize).






RFCW continued

A combination of RFCA, WAKE, TRWAKE, and LSCDRIFT.






Parameter Name UnitsType Default

Description






LSC_LOW_FREQUENCY_CUTOFF1 double-1

Lowest spatial frequency at which low-frequency cutoff filter is 1. If not given, defaults to LOW_FREQUENCY_CUTOFF1.






LSC_HIGH_FREQUENCY_CUTOFF0 double-1

Spatial frequency at which smoothing filter begins for LSC. If not positive, no frequency filter smoothing is done. Frequency is in units of Nyquist (0.5/binsize).






LSC_HIGH_FREQUENCY_CUTOFF1 double-1

Spatial frequency at which smoothing filter is 0 for LSC. If not given, defaults to HIGH_FREQUENCY_CUTOFF0.






LSC_RADIUS_FACTOR double1.7

LSC radius is (Sx+Sy)/2*RADIUS_FACTOR






WAKES_AT_END long 0

Do wake kicks at end of segment (for backward compatibility)?






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 a combination of the RFCA, WAKE, and TRWAKE elements. As such, it provides combined simulation of an rf cavity with longitudinal and transverse wakes, as well as longitudinal space charge.

For the wakes, the input files and their interpretation are identical to WAKE and TRWAKE, except that the transverse and longitudinal wakes are interpreted as the wakes for a single cell of length given by the CELL_LENGTH parameter.

Users should read the entries for WAKE, TRWAKE, and RFCA for more details on this element.

This element simulates longitudinal space charge using the method described in [22]. This is based on the longitudinal space charge impedance per unit length

              [          (    ) ]
         -iZ0-     krb     krb
Zlsc(k ) = πkr2 1 -  γ K1    γ
             b
(127)

N.B.: Do not use CHANGE_T=1 if you have rf cavities that are not at harmonics of one another or if you have other time-dependent elements that are not resonant. Also, if you have harmonic cavities, only use CHANGE˙T on the cavity with the lowest frequency. See the manual page for the RFCA element for more discussion.

RFDF