Beam Phase space in Larmour frame

[Rajni Pande]

Dear Didier,

I am working on a solenoid channel and am interested in seeing the beam phase space in Larmour frame. It would be very useful if this feature is added for a solenoid channel.

Thanks and Regards,
Rajni

[npichoff]

Dear Rajni,

TraceWIN allows following the particle r = sqrt(x^2+y^2) and r' = dr/ds coordinates.
You can plot the (r, r') phase-space evolution, including visualising (r,r') emittance.
It might correspond to your need ?

Best regards.

Nicolas.

[Rajni Pande]

Dear Nicolas,

No, I am not looking for the (r,r') phase space.

As the beam enters the solenoid, the beam experiences rotation. Due to this, coupling between the x and y planes is introduced. Larmour frame is the frame of rotation. By making a transformation to this frame, the coupling between x and y can be removed.
https://people.nscl.msu.edu/~lund/msu/p ... ecture.pdf

Thanks and regards,
Rajni

[npichoff]

Dear Rajni,

Using visualisation of (r, r') is my sugestion.
In a solenoid channel, it has a physical meaning and is "equivalent" of working in "Larmor" frame.
The (r, r') distribution has some sort of "uncoupled continuity" in this axialy-symetrique dynamics.

In a solenoid channel, (x, x) and (y, y') are echanging and orginal (x, x') distribution will become a (y, y') after a 90°transvere rotation. Still tagging it as (x, x') is a non-sens.

In TraceWIN, (x, x') represents the "real" distribution along horizontal direction and (y, y') along vertical direction, whatever the beam configuration and its history. At the end of a calculation, one knows exactly what it represents and what the beam diagnostics should measure.

Best regards.

Nicolas.