Elegant users forum

Hi,

I try to simulate a passive c band cavity streaking experiment.
The beam has a strongly asymmetric current distribution: Narrow peak in the head (few 10 fs) followed by long tail (few ps) obtained from non-linear compression.

In our case the orbit offset is not constant inside the cavity but changes with a rate of around 1e-3.
How is the wake calculated from the orbit through the cavity? (Offset in the beginning of cavity, average offset or splitting ...)

Thank you in advance for you support.
Regards,
Benedikt

Benedikt,

The RFCW element has a parameter N_KICKS which gives the number of integration steps for modeling the cavity. At each integration step, elegant applies the effect of the cavity fields and optionally the wakes and longitudinal space charge. Hence, if the trajectory is changing through the structure, you can capture the effect by making N_KICKS relatively large.

The wakes are supposed to be provided for a single cell of the structure, with the CELL_LENGTH parameter used to scale this to larger integration steps. You could set N_KICKS equal to the number of cells in your C-band structure, which would result in the wakes being computed and applied at the center of each cell.

--Michael