Dear all,
I am quite confused about "&track" options for orbit and momentum.
I understood that, to track stored particles in a ring, I should first verify that the closed orbit exists, then use center_on_orbit = 1. I cannot see any useful/realistic case in which to use center_on_orbit = 0. Maybe for beam injection?
Similarly, I use center_on_momentum_also = 1 and I do not see why/when I shall use it = 0. Maybe when tracking off-momentum beam, e.g. when MALIGN element has DP not null?
Thank you in advance.
Best regards,
Simone
Orbit distortion and beam energy
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michael_borland
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Re: Orbit distortion and beam energy
Simone,
Yes, those features are confusing.
As you guessed, you might want to set center_on_orbit=0 if you are simulating injection or a beam that is off-axis for some other reason. In this case, your beam distribution would contain non-zero centroids that you wouldn't want to obliterate.
Similarly with center_momentum_also. It allows deciding whether the beam's existing momentum centroid should be preserved before tracking. This might again happen during injection, say if there is an energy mismatch.
--Michael
Yes, those features are confusing.
As you guessed, you might want to set center_on_orbit=0 if you are simulating injection or a beam that is off-axis for some other reason. In this case, your beam distribution would contain non-zero centroids that you wouldn't want to obliterate.
Similarly with center_momentum_also. It allows deciding whether the beam's existing momentum centroid should be preserved before tracking. This might again happen during injection, say if there is an energy mismatch.
--Michael