Simulation of transverse multi-bunch instability using the LRWAKE element

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xhs05
Posts: 27
Joined: 29 Nov 2012, 21:43

Simulation of transverse multi-bunch instability using the LRWAKE element

Post by xhs05 » 16 Jul 2017, 08:05

To whom it may concern,

Hi!

Sorry that I've cleared the bug in my scripts. The error is because the input file for the LRWAKE element has all zero values. After generating the correct sdds file as input for LRWAKE, the scripts work properly.

Regards,
Haisheng

michael_borland
Posts: 1452
Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
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Re: Simulation of transverse multi-bunch instability using the LRWAKE element

Post by michael_borland » 17 Jul 2017, 20:21

Haisheng,

Thanks for letting us know.

--Michael

Akhyani
Posts: 16
Joined: 26 Jun 2018, 08:09

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

Post by Akhyani » 18 Sep 2019, 04:16

Dear Michael and all,

I am studying short-range and long-range resistive wall effects in our ring. I used trwake element for calculating short-range effects and I saw the instability around 0.7 mA for single-bunch tracking in zero chromaticity. While using lrwake element for multi-bunch tracking, I expected that the instability threshold will be approximately 100 mA (number of bunches*0.7 mA), but I didn't see any instabilities even at 400 mA. I was wondering what is wrong in my simulations?
Any help would be appreciated. I attached the lattice, bunch and the wake file.

Bests,
--Mina
Attachments
LRwakeRW.rar
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Akhyani
Posts: 16
Joined: 26 Jun 2018, 08:09

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

Post by Akhyani » 22 Sep 2019, 03:05

Any ideas???

lindberg
Posts: 4
Joined: 07 Nov 2018, 14:47

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

Post by lindberg » 02 Oct 2019, 10:12

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 in these two cases one does not expect the thresholds to be the same. What I think you should be doing is continuing to use your short-range wakefield in the TRWAKE element regardless of the number of bunches, and then add on an additional LRWAKE associated with whatever long-range forces you expect. In other words, TRWAKE only affects particles within a given bunch, while LRWAKE only acts on trailing bunches. Hope this helps...

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