strength tapering for energy variation

[esmahmadi]

Dear Micheal and Others
There is a definition in the MADx that calculates the adjustment to the strengths of elements to account for small momentum
variations through RF cavities or synchrotron radiation. I wonder to know there is any equivalent definition for it in the Elegant? I tried to consider the tapered strength by using FSE, but the lattice parameters were very different from the original ones in MADX.
I appreciate any help and comments.

Regards
Esmaeil

[michael_borland]

Esmaeil,

I'm not sure I quite follow what you are trying to do. In elegant, the strengths of elements are generally specified in geometric terms, so they automatically account for the energy of the beam, assuming that the elements are set up in the real world with the energy variation in mind. Are you seeking to specify the strengths in absolute terms (e.g., quadrupoles in T/m)?

--Michael

[esmahmadi]

Dear Micheal,
Thank you very much for your comment. I apologize for the late reply.
I am using the geometric term for quadrupole (1/m^2).
The problem is that The constant energy loss in the arcs, in combination with the re-acceleration in the straight RF sections, causes a huge closed orbit distortion in the horizontal direction. In MADX, it is cured by adding some quadrupoles to the main field of dipole and quadrupole magnets.
I have attached the files which I am using for my calculations.
I really appreciate any help you can provide.

Best regards
Esmaeil

[michael_borland]

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 &moments_output command provides fully self-consistent beamsize computations, including synchrotron radiation effects on both the trajectory and the effective strength of elements.

--Michael

[esmahmadi]

Dear Michael,
Many thanks for your comment.

Best Regards
Esmaeil