Question about FSE, FSE_DIPOLE, FSE_QUADRUPOLE

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sagan
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Joined: 20 Mar 2020, 13:41

Question about FSE, FSE_DIPOLE, FSE_QUADRUPOLE

Post by sagan » 20 May 2022, 14:53

Questions:
1) Is setting FSE to some value the same as setting both FSE_DIPOLE and FSE_QUADRUPOLE to that value?
2) If FSE, FSE_DIPOLE, and FSE_QUADRUPOLE are all set to different values what is the result?

michael_borland
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Location: Argonne National Laboratory
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Re: Question about FSE, FSE_DIPOLE, FSE_QUADRUPOLE

Post by michael_borland » 23 May 2022, 13:26

The FSE factor is applied to all fields, including dipole, quadrupole, and higher multipoles.

FSE_DIPOLE is the same, but it does not affect the quadrupole or sextupole terms.

FSE_QUADRUPOLE affects only the quadrupole terms (normal and skew).

So if you compare setting (FSE=x,FSE_DIPOLE=FSE_QUADRUPOLE=0) to setting (FSE=0, FSE_DIPOLE=FSE_QUADRUPOLE=x), you'll find that the agree in linear order only. The reason is that FSE affects the sextupole and higher terms, whereas FSE_DIPOLE affects octupole and higher terms (in addition to the dipole).

--Michael

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