TMCI simulation w/o radiation damping

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Shichang
Posts: 11
Joined: 31 May 2017, 07:32

TMCI simulation w/o radiation damping

Post by Shichang » 14 Mar 2019, 20:54

Hi Michael,

We want to simulate TMC-Instability w/ or w/o radiation damping effect, here we have two more problems.
  • Is there any way to exclude damping effect but reserve longitudinal motion? In case of we utilize double-frequency RF or triple-frequency RF system to include nonlinear synchrotron motion.
  • We had tried to set DAMPING=0 in SREFFECTS to weaken damping effects, however the longitudinal parameters, St, Sdelta, etc., will become uncontrollable due to insufficient longitudinal focusing. Do you have any better suggestions to handle with this?
Best regards,
Jiang

michael_borland
Posts: 1933
Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
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Re: TMCI simulation w/o radiation damping

Post by michael_borland » 22 May 2019, 14:28

Jiang,

You could get rid of the SREFFECTS element and instead use a MALIGN element with a DP value equal to -U0/E, where U0 is the energy loss per turn and E is the beam energy. That will allow setting the rf systems at the right synchronous phase, but there shouldn't be any damping.

--Michael

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