RFDF—A simple traveling or standing wave deflecting RF cavity.

A simple traveling or standing wave deflecting RF cavity.
Parallel capable? : yes
GPU capable? : no
Back-tracking capable? : no


Parameter Name	Units	Type	Default	Description

L	M	double	0.0	length

PHASE	DEG	double	0.0	phase

TILT	RAD	double	0.0	rotation about longitudinal axis

FREQUENCY	HZ	double	2856000000	frequency

VOLTAGE	V	double	0.0	voltage

FSE		double	0.0	Fractional Strength Error

B2		double	0.0	Normalized sextupole strength, kick=(1+b2*(x-y)/2)...

TIME_OFFSET	S	double	0.0	time offset (adds to phase)

N_KICKS		long	0	number of kicks (0=autoscale)

PHASE_REFERENCE		long	0	phase reference number (to link with other time-dependent elements)

STANDING_WAVE		short	0	If nonzero, then cavity is standing wave.

VOLTAGE_WAVEFORM		STRING	NULL	<filename>=<x>+<y> form specification of input file giving voltage waveform factor vs time

VOLTAGE_PERIODIC		short	0	If non-zero, voltage waveform is periodic with period given by time span.

ALIGN_WAVEFORMS		short	0	If non-zero, waveforms’ t=0 is aligned with first bunch arrival time.

VOLTAGE_NOISE		double	0.0	Rms fractional noise level for voltage.

PHASE_NOISE	DEG	double	0.0	Rms noise level for phase.

GROUP_VOLTAGE_NOISE		double	0.0	Rms fractional noise level for voltage linked to group.

GROUP_PHASE_NOISE	DEG	double	0.0	Rms noise level for phase linked to group.

VOLTAGE_NOISE_GROUP		long	0	Group number for voltage noise.


Parameter Name	Units	Type	Default	Description

PHASE_NOISE_GROUP		long	0	Group number for phase noise.

START_PASS		long	-1	If non-negative, pass on which to start modeling cavity.

END_PASS		long	-1	If non-negative, pass on which to end modeling cavity.

START_PID		long	-1	If non-negative, lowest particle ID to which deflection is applied.

END_PID		long	-1	If non-negative, highest particle ID to which deflection is applied.

DRIFT_MATRIX		short	0	If non-zero, calculations involving matrices assume this element is a drift space.

DX	M	double	0.0	misalignment

DY	M	double	0.0	misalignment

DZ	M	double	0.0	misalignment

MAGNETIC_DEFLECTION		short	0	If non-zero, deflection is assumed to be performed by a magnetic field, rather than electric field (default).

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 cavity provides a transverse deflection that is constant as a function of transverse coordinates. It is probably the best model for a real cavity, because real cavities contain a mixture of TM- and TE-like modes that result in a uniform deflection.

For simplicity of use, the deflection is specified as a voltage, even though it originates in a magnetic field. The magnetic field is

The change in momenta (in units of mc) in passing through a slice of length ΔL is

Explanation of <filename>=<x>+<y> format: Several elements in elegant make use of data from external files to provide input waveforms. The external files are SDDS files, which may have many columns. In order to provide a convenient way to specify both the filename and the columns to use, we frequently employ <filename>=<x>+<y> format for the parameter value. For example, if the parameter value is waveform.sdds=t+A, then it means that columns t and A will be taken from file waveform.sdds. The first column is always the independent variable (e.g., time, position, or frequency), while the second column is the dependent quantity.

10.90 RFDF—A simple traveling or standing wave deflecting RF cavity.