Elegant users forum

Arnold, I should note there is one pitfall to using CHANGE_T=1 on RFCA elements: it only works correctly if all rf elements have frequencies that are harmonics of one another. In addition, one should set CHANGE_T=1 on the rf element with the lowest frequency. Finally, no other time-dependent element...

Unless your system has significant nonlinearities, I think using n_particles_per_bunch=1e5 is unnecessary. A single particle started at the centroid location should follow the centroid perfectly in a linear system. Which part of the simulation is too time-consuming, the tracking or the post-tracking...

Chao,

I think it is just the L parameters on your ILMATRIX definitions are not quite right. If I add ILMAT1.L and ILMAT2.L, I get 2303.999099999, not 2304.

--Michael

After looking into this more, I realized that elegant deliberately was not including this effect in twiss_output computations. The reason is that it requires including synchrotron radiation effects transport matrix. I'll have a limited work-around for this in the next release. Meanwhile, the &moment...

This runs fine for me. If this is the same issue that Bob Soliday was looking into for you, the files he forwarded to me had BIN_SIZE=0 on FTRFMODE, which caused a crash in the parallel version. In the serial version, it didn't crash but the element was non-functional. The manual incorrectly states ...

Samira, I think the problem is partly that your skew quadrupoles are relatively weak. For example, if I multiply the skew strengths by 100, there's a clear effect on Sx and Sy in the .sig file. Also, please note that &twiss_output does not give trustworthy results in the presence of strong coupling....

This is a workable approach if you only have one bunch at a time, since for each simulation step the macroparticles have the same charge.

--Michael

Arnold, There aren't any dangers in using CHANGE_T=1 and REFERENCE_CORRECTION=1 together. The warning about using care with reference correction was intended to address the possibility that someone would use reference correction to compensate for having a grossly inadequate number of slices. It thin...

Wei-Hou,

Sorry, I didn't notice that you were loading an energy profile.

There does seem to be a bug in the twiss computation for this case. I'll fix it for the next release. The tracking results should be fine.

--Michael

Chao, We have the same configuration with the APS linac: quadrupoles over top of the structures. I also split the linac into many sections, then put very thin quadrupoles between them. Using the kick-based model should be more accurate, but I think you'll see an effect only if your beam is not fully...