Summer 2021 Phys 659 Work

These codes are used to simulate a Structure-Based Wakefield Acceleration.

Tremaine-Roz C++ Code

A C++ based simulation code that has two possibilities for runs: an on-axis representation of what's going on (including E and B fields) and a scan over x and y at some target z.

General Comments

Files to keep together

In order to run the main code (run_tr_3d_scan.cpp or run_tr_3d.cpp), two other files are required to be in the same directory, which are the tremaine_roz.cpp and tremaine_roz.h.

How to run this code

Once the three files are together in a directory, the Windows commands are:

g++ mainfile.cpp -lm -o wake - This looks through the three files and creates an executable file

.\wake.exe - This executable file actually runs the code and, for the scan, will have output as the scan processes the data for each (x,y) point.

On-Axis run

run_tr_3d.cpp is for the on-axis run. The output is given in two files: wake_ExEyEzBxByBz.dat and wake_z_wz.dat.

Scan over X and Y

The output electric and magnetic field data is given in the file wake_2Dsurf.dat with extra data given in wake_z_wz.dat. Other output can also be chosen, but see the code in here and documentation to add other parameters. The wake_2dsurf.dat file is what has the x, y, z, Ex, Ey, Bx, and By data and are delimited using a space and can be extracted using python to plot (ScannedPlots.ipynb). The layout is seen below:

  x      y    z   Ex  Ey  Bx  By
-----  ----- --- --- --- --- ---
 -5.5   1.5   0   0   0   0   0
...
 5.5    1.5   0   0   0   0   0

Plotting

The wakefields are plotted in the file ScannedPlots.ipynb. In order to get the wakefields, the equation is implemented.

WARP Code

This python-based code is powerful in dumping large amounts of data into HDF5 files and continuing its calculations through many different timesteps.

Running the code

This code is run on the NICADD cluster as there is no WARP option for Windows and because the HDF5 files are rather memory intensive. It's python-based, so a connection between the cluster and the personal Windows computer is created to run Jupyterlab through Chrome. A Diag directory is created and the HDF5 files dumped for certain timesteps (defined in the file).

HDF5 Files and Plot Creation

The HDF5 file has a nested format for the data and generally needs investigating if unfamiliar with the output of a specific run. Below is the current layoutfor the HDF5 files created from the testingawacode-WORKS.ipynb.

-Data
 -Timestep (eg "500")
  -Fields
   -B
    -x (data)
    -y (data)
    -z (data)
   -E
    -x (data)
    -y (data)
    -z (data)
   -J
    -x (data)
    -y (data)
    -z (data)
   -Rho (data)
  -Particles
   -Helium0+
    -Momentum 
     -x (data)
     -y (data)
     -z (data)
    -positionOffset
     -x (data)
     -y (data)
     -z (data)
   ...

Plotting is done using WARPplotting.ipynb, where the HDF5 file is read and data taken from it for a specific timestep, described at the beginning of the file.

Fall 2021 Phys 659 Work

WARPX

Matrix Analysis of Single-Shot Wakefield Measurement System

This analysis is based off of the article Single-shot wakefield measurement system in the Physical Review Accelerators and Beams 21, 062801 (2018). The system outputs the beam to go through a transverse deflecting cavity (TDC), two quads (not taken into account here), and a spectrometer.

The TDC has a transport matrix in phase space of:

The drift transport matrix is:

And, finally, the spectrometer acts like a dipole and has a transport matrix of:

The code for this is a simple jupyter notebook, but does require a specific library of sobol. For more information, go to Sobol.

The single jupyter notebook is all that is needed and will be commented out shortly.