turning off transverse beam dynamics

[Philippe Piot]

Hello,
Is there a way to run ELEGANT in a "LiTracK" fashion only looking at longitudinal dynamics? I naively thought imposing extremely low transverse emittance would do the trick. I basically want to force the transverse phase space to keep its zero emittance along the linac and only look at the longitudinal dynamics. Thank you, -- Philippe.

[michael_borland]

Philippe,

There's no clean way to do this. You can try resetting the transverse coordinates to zero after each element, but you'll still get transverse effects inside the elements.

Code: Select all

&insert_elements
	name = *, type = *,
	element_def = "M0: magnify,mx=0,mxp=0,my=0,myp=0"
	add_at_start = 1,
	add_at_end = 1,
&end

After doing this, the .sig and .cen files will need to be filtered to keep only the data after each M0 element, e.g.,

Code: Select all

sddsprocess run.sig -match=col,ElementName=M0

--Michael

[Philippe Piot]

Hello Michael,
Thank you, this seems to do the job for now. I have one more favor would it be possible to have the longitudinal emittance in the sigmas files so to see its evolution along the beamline? This would be convenient. Right now I use sddsprocess $1.sig -define=column,ez,"Ss Ss * Sdelta * Sdelta * s56 s56 * - sqrt",units=m . Thank you, -- Philippe.

[Philippe Piot]

Hello Michael,
Actually, I was a bit too fast in my earlier reply. Inside a bunch compressor, the method does not work. because of the dispersion (then setting MX=0 mess up the compression) but I think it is OK as far as my problem is concerned. Best, -- Philippe.