Elegant users forum

Hi Michael,

I'm using elegant 33.0.2.

I've found that the ZTRANSVERSE element doesn't work well when I use Pelegant to simulate the transverse single-bunch instability. The problem is that no output wake data and the beam moment data when I set {wakes="trwake.sdds"] in the ZTRANSVERSE element.

However, the output file "trwake.sdds" shows when I run the same script by elegant instead of Pelegant. Would you like to double check whether this is a bug or not?

Thank!

Regards,
Haisheng

Haisheng,

The parallel version doesn't have the feature of dumping the wake output. The manual should mention this, but it was overlooked.

The reason is that wake output is considered a debugging feature.

--Michael

Hi Michael,

Thanks for the clarification!

Regards,
Haisheng

This is actually not a response to the problem of xhs05, but another problem i encountered using ZTRANSVERSE. Should I better open a new topic ?

Anyway, I also want to study instabilities with the element ZTRANSVERSE, and as first approach I set up a very simple periodic structure (a ring) consisting of a ILMATRIX, a CAVity and broadband resonator given by ZTRANSVERSE. I used as broadband parameters R=1e6Ohm/m , f_{reso}=11MHz and Q=1.

Find here some extracts from the elegant (parallel version) output:
This is elegant 28.1.0, Jul 24 2015, ...
...
ZTRANSVERSE,CHARGE=1.602E-10,BROADBAND=1,RS=1.0E6,Q=1.,FREQ=11.E06,BIN_SIZE=0

In the manual it was written "(use 0 for autosize)", for BIN_SIZE, however I got the following error message.

error: bin_size must be positive for ZTRANSVERSE element


In the following I tried a non-zero BIN_SIZE, but elegant commented that my BIN_SIZE is too large and rescaled it to values in the area ~1e-12 -- 1e-13 and complained about the necessary small BIN_SIZE.

Actually I not only tried FREQ=11.E06, also even FREQ=11.E09 whiich seems to a rather realistic BBR-frequency for the description of the total transverse impedance of a synchrotron light source.

So I wonder how to use ZTRANSVERSE to include a realistic trans BBR in a ring. Could you help me out ? Consider that I've just started using ELEGANT.

Thank you
Thomas Guenzel

Thomas,

Here's an example of using ZLONGIT for a broad-band impedance. ZTRANSVERSE should be very similar. Let me know if this doesn't help resolve the difficulties.

--Michael

Dear Michael,

thank you very much.

I will try out.

Regards,
Thomas