diff options
Diffstat (limited to 'Examples')
| -rwxr-xr-x | Examples/Tests/plasma_lens/analysis.py | 102 | ||||
| -rw-r--r-- | Examples/Tests/plasma_lens/inputs_3d | 50 |
2 files changed, 152 insertions, 0 deletions
diff --git a/Examples/Tests/plasma_lens/analysis.py b/Examples/Tests/plasma_lens/analysis.py new file mode 100755 index 000000000..b348a3053 --- /dev/null +++ b/Examples/Tests/plasma_lens/analysis.py @@ -0,0 +1,102 @@ +#! /usr/bin/env python + +# Copyright 2021 David Grote +# +# This file is part of WarpX. +# +# License: BSD-3-Clause-LBNL + + +""" +This script tests the plasma lens. +The input file sets up a series of plasma lens and propagates a particle through them. +The final position is compared to the analytic solution. +The motion is slow enough that relativistic effects are ignored. +""" + +import sys +import os +import yt +import numpy as np +from scipy.constants import e, m_e, c +yt.funcs.mylog.setLevel(0) +sys.path.insert(1, '../../../../warpx/Regression/Checksum/') +import checksumAPI + +filename = sys.argv[1] +ds = yt.load( filename ) +ad = ds.all_data() + +# Get final position of the particles +# The sorting by id is to get them in the correct order +# There are two particles, one moves in x, the other in y. +r_id = ad['electrons', 'particle_id'].v + +xx_sim = ad['electrons', 'particle_position_x'].v[np.argsort(r_id)][0] +yy_sim = ad['electrons', 'particle_position_y'].v[np.argsort(r_id)][1] +zz_sim0 = ad['electrons', 'particle_position_z'].v[np.argsort(r_id)][0] +zz_sim1 = ad['electrons', 'particle_position_z'].v[np.argsort(r_id)][1] + +ux_sim = ad['electrons', 'particle_momentum_x'].v[np.argsort(r_id)][0]/m_e +uy_sim = ad['electrons', 'particle_momentum_y'].v[np.argsort(r_id)][1]/m_e + + +def applylens(x0, vx0, vz0, lens_length, lens_strength): + """Given the initial position at the start of the lens, + calculate the end position at the exit. + This assumes harmonic motion.""" + w = np.sqrt(e/m_e*lens_strength) + A = np.sqrt(x0**2 + (vx0/w)**2) + phi = np.arctan2(-vx0, w*x0) + t = lens_length/vz0 + x1 = A*np.cos(w*t + phi) + vx1 = -w*A*np.sin(w*t + phi) + return x1, vx1 + +plasma_lens_period = float(ds.parameters.get('particles.repeated_plasma_lens_period')) +plasma_lens_starts = [float(x) for x in ds.parameters.get('particles.repeated_plasma_lens_starts').split()] +plasma_lens_lengths = [float(x) for x in ds.parameters.get('particles.repeated_plasma_lens_lengths').split()] +plasma_lens_strengths = [eval(x) for x in ds.parameters.get('particles.repeated_plasma_lens_strengths').split()] + +clight = c + +x0 = float(ds.parameters.get('electrons.multiple_particles_pos_x').split()[0]) +y0 = float(ds.parameters.get('electrons.multiple_particles_pos_y').split()[1]) +z0 = float(ds.parameters.get('electrons.multiple_particles_pos_z').split()[0]) +ux0 = float(ds.parameters.get('electrons.multiple_particles_vel_x').split()[0])*c +uy0 = float(ds.parameters.get('electrons.multiple_particles_vel_y').split()[1])*c +uz0 = eval(ds.parameters.get('electrons.multiple_particles_vel_z').split()[0])*c + +tt = 0. +xx = x0 +yy = y0 +zz = z0 +ux = ux0 +uy = uy0 +uz = uz0 + +for i in range(len(plasma_lens_starts)): + z_lens = i*plasma_lens_period + plasma_lens_starts[i] + dt = (z_lens - zz)/uz + tt = tt + dt + xx = xx + dt*ux + yy = yy + dt*uy + xx, ux = applylens(xx, ux, uz, plasma_lens_lengths[i], plasma_lens_strengths[i]) + yy, uy = applylens(yy, uy, uz, plasma_lens_lengths[i], plasma_lens_strengths[i]) + dt = plasma_lens_lengths[i]/uz + tt = tt + dt + zz = z_lens + plasma_lens_lengths[i] + +dt0 = (zz_sim0 - zz)/uz +dt1 = (zz_sim1 - zz)/uz +xx = xx + dt0*ux +yy = yy + dt1*uy + +assert abs(xx - xx_sim) < 0.011, Exception('error in x particle position') +assert abs(yy - yy_sim) < 0.011, Exception('error in y particle position') +assert abs(ux - ux_sim) < 70., Exception('error in x particle velocity') +assert abs(uy - uy_sim) < 70., Exception('error in y particle velocity') + +test_name = os.path.split(os.getcwd())[1] +checksumAPI.evaluate_checksum(test_name, filename) + diff --git a/Examples/Tests/plasma_lens/inputs_3d b/Examples/Tests/plasma_lens/inputs_3d new file mode 100644 index 000000000..fa19685a2 --- /dev/null +++ b/Examples/Tests/plasma_lens/inputs_3d @@ -0,0 +1,50 @@ +# Maximum number of time steps +max_step = 97 + +# number of grid points +amr.n_cell = 16 16 16 + +amr.max_level = 0 + +# Geometry +geometry.coord_sys = 0 # 0: Cartesian +geometry.prob_lo = -1.0 -1.0 0.0 # physical domain +geometry.prob_hi = 1.0 1.0 2.0 + +boundary.field_lo = pec pec pec +boundary.field_hi = pec pec pec +boundary.particle_lo = absorbing absorbing absorbing +boundary.particle_hi = absorbing absorbing absorbing + +warpx.do_pml = 0 +warpx.const_dt = 1.e-6 +warpx.do_electrostatic = labframe + +# Algorithms +algo.particle_shape = 1 + +# particles +particles.species_names = electrons + +electrons.charge = -q_e +electrons.mass = m_e +electrons.injection_style = "MultipleParticles" +electrons.multiple_particles_pos_x = 0.5 0. +electrons.multiple_particles_pos_y = 0. 0.4 +electrons.multiple_particles_pos_z = 0.05 0.05 +electrons.multiple_particles_vel_x = 0. 0. +electrons.multiple_particles_vel_y = 0. 0. +electrons.multiple_particles_vel_z = 0.02e6/clight 0.02e6/clight +electrons.multiple_particles_weight = 1. 1. + +particles.E_ext_particle_init_style = repeated_plasma_lens +particles.repeated_plasma_lens_period = 0.5 +particles.repeated_plasma_lens_starts = 0.1 0.11 0.12 0.13 +particles.repeated_plasma_lens_lengths = 0.1 0.11 0.12 0.13 +particles.repeated_plasma_lens_strengths = 0.07 0.06 0.06 0.03 + +# Diagnostics +diagnostics.diags_names = diag1 +diag1.intervals = 97 +diag1.diag_type = Full +diag1.electrons.variables = ux uy uz |