Search found 4 matches

by lindberg
04 Oct 2019, 15:24
Forum: Ring Tracking
Topic: Study of TMCI
Replies: 19
Views: 12738

Re: Study of TMCI

I'm not sure why you think this is "underestimated." Your impedance is rather strong and the microwave instability threshold should be pretty low. If you reduce Ra to, say 20 MOhm then the threshold should increase to ~0.8 mA. One thing to note is that with only 10,000 particles the microwave instab...
by lindberg
02 Oct 2019, 10:12
Forum: Ring Tracking
Topic: Simulation of transverse multi-bunch instability using the LRWAKE element
Replies: 6
Views: 4681

Re: Simulation of transverse multi-bunch instability using the LRWAKE element

I wasn't able to parse the attached files, so I'm not completely sure what you're doing here. Based solely upon your description, though, it sounds like you are using the same wakefield file for short- and long-range stability simulations. However, since the instability mechanism is quite different ...
by lindberg
02 Oct 2019, 09:56
Forum: Ring Tracking
Topic: Study of TMCI
Replies: 19
Views: 12738

Re: Study of TMCI

I checked things out, and the reason for the particle loss has nothing to do with the impedance; eliminating the ZLONGIT element leads to the same loss. It seems to me that the RFCA element is not set up properly for a single RF cavity. For V=4.1 MV I find that if you change the present settings of ...
by lindberg
07 Nov 2018, 15:04
Forum: Ring Tracking
Topic: Study of TMCI
Replies: 19
Views: 12738

Re: Study of TMCI

Yes. Short-range transverse wakefields (impedances) are modeled using the TRWAKE or (ZTRANSVERSE) element. One published example that uses ZTRANSVERSE to determine the transverse instability threshold is described in Section IV of PRSTAB 19, 124402 (2016); there are many other examples [e.g., end of...