SREFFECTS

Simulation of synchrotron radiation effects (damping and quantum excitation).

Parameter Name	Units	Type	Default	Description
JX		double	1	x damping partition number
JY		double	1	y damping partition number
JDELTA		double	2	momentum damping partition number
EXREF	$m$	double	0.0	reference equilibrium x emittance
EYREF	$m$	double	0.0	reference equilibrium y emittance
SDELTAREF	$m$	double	0.0	reference equilibrium fractional momentum spread
DDELTAREF		double	0.0	reference fractional momentum loss (per turn)
PREF	$m_{e}c$	double	0.0	reference momentum (to which other reference values pertain)
COUPLING		double	0.0	x-y coupling
FRACTION		double	1	fraction of implied SR effect to simulate with each instance
DAMPING		long	1	include damping, less rf effects?
QEXCITATION		long	1	include quantum excitation?
LOSSES		long	1	include average losses?

This element allows simulation of synchrotron radiation effects in a lumped fashion for quick, approximate results. There are two ways to set up the element: explicit initialization or automatic initialization.

In explicit initialization, the user supplies the quantities EXREF, EYREF, SDELTAREF, DDELTAPREF, and PREF. These are, respectively, the reference values for the x-plane emittance, y-plane emittance, fractional momentum spread, energy loss per turn, and momentum. The first four values pertain to the reference momentum. JX, JY, and JDELTA may also be given, although the defaults work for typical lattices.

In automatic initialization, the user turns on the radiation integral feature in twiss_output, causing elegant to automatically compute the above quantities. The COUPLING parameter can be used to change the partitioning of quantum excitation between the horizontal and vertical planes.