A firstorder matrix RF cavity with exact phase dependence, plus optional amplitude and phase
modulation.
Parallel capable? : yes
GPU capable? : no
Backtracking capable? : no
Parameter Name  Units  Type  Default  Description 
L  M  double  0.0  length 
VOLT  V  double  0.0  nominal voltage 
PHASE  DEG  double  0.0  nominal phase 
FREQ  Hz  double  500000000  nominal frequency 
Q  double  0.0  cavity Q 

PHASE_REFERENCE  long  0  phase reference number (to link with other timedependent elements) 

AMMAG  double  0.0  magnitude of amplitude modulation (fraction value) 

AMPHASE  DEG  double  0.0  phase of amplitude modulation 
AMFREQ  Hz  double  0.0  frequency of amplitude modulation 
AMDECAY  1∕s  double  0.0  exponential decay rate of amplitude modulation 
PMMAG  DEG  double  0.0  magnitude of phase modulation 
PMPHASE  DEG  double  0.0  phase of phase modulation 
PMFREQ  Hz  double  0.0  frequency of phase modulation 
PMDECAY  1∕s  double  0.0  exponential decay rate of phase modulation 
FIDUCIAL  STRING  NULL  mode for determining fiducial arrival time (light, tmean, first, pmaximum) 

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

This element is very similar to the RFCA element, except that the amplitude and phase of the cavity can be modulated.
The phase convention is as follows, assuming a positive rf voltage: PHASE=90 is the crest for acceleration. PHASE=180 is the stable phase for a storage ring above transition without energy losses.
The element works by first computing the fidicial arrival time
. Using this, the effective voltage is computed using the amplitude modulation parameters, according to
 (92) 
where V _{0} is the nominal cavity voltage VOLT, A_{am} is AMMAG, ω_{am} is the angular frequency corresponding to AMFREQ, ϕ_{am} is the amplitude modulation phase corresponding to AMPHASE (converted from degrees to radians), and α_{am} is AMDECAY.
The phase of the phase modulation is computed using
 (93) 
where ω_{pm} is the angular frequency corresponding to PMFREQ and Δϕ_{pm} is the phase offset corresponding to PMPHASE (converted from degrees to radians). The rf phase for the centroid is then computed using
 (94) 
where ω_{0} is the nominal rf angular frequency (corresponding to FREQ), ϕ_{0} corresponds to PHASE (converted to radians), Φ_{m} corresponds to PMMAG (converted to radians), and α_{pm} corresponds to PMDECAY.
The effective instantaneous rf angular frequency is
 (95) 
Using all of the above, the voltage seen by a particle arriving at time t is then
 (96) 
MONI