Confusion to the RFMODE element

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michael_borland
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Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
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Re: Confusion to the RFMODE element

Post by michael_borland » 02 Mar 2018, 18:41

Jiang,

The problem is that your RFMODE-based simulation uses only a single bunch, which will have large transients and compression from the cavity wakes. To solve this, you can use pseudo-multi-bunch mode, which involves tracking one particle distribution but driving the cavity fields as if you had a series of equispaced bunches. The attached files show how to do this. The result is good agreement of the two methods.
twoMethods.png
As for the phase walk-off, this is a problem with the feedback implementation. The beam and rf systems walk off together, locked in phase, but drifting relative to the absolute clock. We don't have a ready solution now, but it seems harmless.

--Michael

michael_borland
Posts: 1795
Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
Contact:

Re: Confusion to the RFMODE element

Post by michael_borland » 02 Mar 2018, 18:41

Forgot the files.

--Michael
Attachments
2018-03-02-mod.zip
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