cavity field-map characterization

Description

Characterize the beam-dynamics properties in a cavity (1D, and 3D) based on early work with A. Halavanau and T. Xu

file list:

• field for ASTRA :
  • 3D_asta.* (6 files) contains the 3D field for a TESLA superconducting cavity for ASTRA
  • Ez_axis.dat represents the field on the axis for astra (z, Ez)
• ASTRA input file
  • 9-cell3D.in: input file for tracking in a 3D map only and vary the phase from -100 to 100 deg (produces 41 outputs)
  • 9-celltest.in: input file with run #1 trackin in 1D file and run #2 tracking in 3D map
• Scripts:
  • MakeGridBeam.py produces a distribution with a small longitudinal size and macroparticle arranged on a 2D grid in (x,y). The transverse momentum is set to zero
  • SeeCouplerKick.py generate a map of the transverse kick (using outputs from runs 1 and 2 produced by 9-celltest.in)
  • MomentumAnalysis.py computes the variation of kick strength as a function of phase (from the output from 9-cell3D.in)

Running the example

• generate kick 2D map:

  • generate the input distribution python MakeGridBeam.py
  • copy distribution to the proper file name (use by Astra) cp grid_distrib.ini dist.ini
  • run ASTRA astra 9-celltest.in
  • produce 2D map ````python SeeCouplerKick.py```. The Figure below displays the output you should get by running the script for the field maps considered in this example.

• analyze multipole components of the kick as a function of phase (following A. Halavanau et al. PRAB 20, 040102, 2017 originally worked out by Z. Li et al, proc. PAC93, p. 179 (1993):

  • generate the input distribution python MakeGridBeam.py
  • copy distribution to the proper file name (use by Astra) cp grid_distrib.ini dist.ini
  • run ASTRA astra 9-cell3D.in
  • produce 2D map python MomentumAnalysis.py The Figure below displays the output you should get by running the script for the field maps considered in this example.

Other files/directories

• the directory figs contains the figure shown in this README.md file.