1 files changed, 53 insertions, 0 deletions
diff --git a/Examples/Modules/RigidInjection/analysis_rigid_injection_BoostedFrame.py b/Examples/Modules/RigidInjection/analysis_rigid_injection_BoostedFrame.py
new file mode 100755
index 000000000..497a30097
--- /dev/null
+++ b/Examples/Modules/RigidInjection/analysis_rigid_injection_BoostedFrame.py
@@ -0,0 +1,53 @@
+#! /usr/bin/env python
+
+'''
+Analysis script of a WarpX simulation of rigid injection in a boosted frame.
+
+A Gaussian electron beam starts from -5 microns, propagates rigidly up to
+20 microns after which it expands due to emittance only (the focal position is
+20 microns). The beam width is measured after ~50 microns, and compared with
+the theory (with a 5% error allowed).
+
+The simulation runs in a boosted frame, and the analysis is done in the lab
+frame, i.e., on the back-transformed diagnostics.
+'''
+
+import sys, os, yt, glob
+import numpy as np
+import scipy.constants as scc
+import read_raw_data
+yt.funcs.mylog.setLevel(0)
+
+# filename = sys.argv[1]
+
+def get_particle_field(snapshot, species, field):
+    fn = snapshot + '/' + species
+    files = glob.glob(os.path.join(fn, field + '_*'))
+    files.sort()
+    all_data = np.array([])
+    for f in files:
+        data = np.fromfile(f)
+        all_data = np.concatenate((all_data, data))
+    return all_data
+
+# Read data from back-transformed diagnostics
+snapshot = './lab_frame_data/snapshot00001'
+header   = './lab_frame_data/Header'
+allrd, info = read_raw_data.read_lab_snapshot(snapshot, header)
+z = np.mean( get_particle_field(snapshot, 'beam', 'z') )
+w = np.std ( get_particle_field(snapshot, 'beam', 'x') )
+
+# initial parameters
+z0 = 20.e-6
+w0 = 1.e-6
+theta0 = np.arcsin(0.1)
+
+# Theoretical beam width after propagation if rigid ON
+wth = np.sqrt( w0**2 + (z-z0)**2*theta0**2 )
+error = np.abs((w-wth)/wth)
+
+# Print error and assert small error
+print("Beam position: " + str(z))
+print("Beam width   : " + str(w))
+print("error: " + str(error))
+assert( error < 0.03 )