diff options
| -rwxr-xr-x | Examples/Tests/RepellingParticles/analysis_repelling.py | 78 | ||||
| -rw-r--r-- | Examples/Tests/RepellingParticles/inputs_2d | 53 | ||||
| -rw-r--r-- | Regression/Checksum/benchmarks_json/RepellingParticles.json | 36 | ||||
| -rw-r--r-- | Regression/WarpX-tests.ini | 16 |
4 files changed, 183 insertions, 0 deletions
diff --git a/Examples/Tests/RepellingParticles/analysis_repelling.py b/Examples/Tests/RepellingParticles/analysis_repelling.py new file mode 100755 index 000000000..25f1fe977 --- /dev/null +++ b/Examples/Tests/RepellingParticles/analysis_repelling.py @@ -0,0 +1,78 @@ +#! /usr/bin/env python +# +# Copyright 2021 Remi Lehe +# +# This file is part of WarpX. +# +# License: BSD-3-Clause-LBNL + +""" +This script tests the interaction between 2 electron macroparticles. + +The macroparticles are moving towards each other and slow down due to the +repelling force between charges of the same sign. The particles should +be moving slow enough for relativistic effects to be negligible. In +this case the conservation of energy gives: + +beta(t)^2 = beta(0)^2 + 2 * w * re * log(d(0)/d(t)) + +where: +re is the classical electron radius +w is the weight of the individual macroparticles +d is the distance between them +beta is the velocity normalized by the speed of light +""" +import numpy as np +from scipy.constants import m_e, c, physical_constants +import sys, re +import yt +import glob +import matplotlib.pyplot as plt +yt.funcs.mylog.setLevel(0) + +# Check plotfile name specified in command line +last_filename = sys.argv[1] +filename_radical = re.findall('(.*?)\d+/*$', last_filename)[0] + +# Loop through files, and extract the position and velocity of both particles +x1 = [] +x2 = [] +beta1 = [] +beta2 = [] +for filename in sorted(glob.glob(filename_radical + '*')): + print(filename) + ds = yt.load(filename) + ad = ds.all_data() + + x1.append( float(ad[('electron1','particle_position_x')]) ) + x2.append( float(ad[('electron2','particle_position_x')]) ) + beta1.append( float(ad[('electron1','particle_momentum_x')])/(m_e*c) ) + beta2.append( float(ad[('electron2','particle_momentum_x')])/(m_e*c) ) + +# Convert to numpy array +x1 = np.array(x1) +x2 = np.array(x2) +beta1 = np.array(beta1) +beta2 = np.array(beta2) + +# Plot velocities, compare with theory +w = 5.e12 +re = physical_constants['classical electron radius'][0] +beta_th = np.sqrt( beta1[0]**2 - 2*w*re*np.log( (x2[0]-x1[0])/(x2-x1) ) ) +plt.plot( beta1, '+', label='Particle 1' ) +plt.plot( -beta2, 'x', label='Particle 2' ) +plt.plot( beta_th, '*', label='Theory' ) +plt.legend(loc=0) +plt.xlabel('Time (a.u.)') +plt.ylabel('Normalized velocity') +plt.savefig('Comparison.png') + +# Check that the results are close to the theory +assert np.allclose( beta1[1:], beta_th[1:], atol=0.01 ) +assert np.allclose( -beta2[1:], beta_th[1:], atol=0.01 ) + +# Run checksum regression test +sys.path.insert(1, '../../../../warpx/Regression/Checksum/') +import checksumAPI +test_name = last_filename[:-9] +checksumAPI.evaluate_checksum(test_name, last_filename) diff --git a/Examples/Tests/RepellingParticles/inputs_2d b/Examples/Tests/RepellingParticles/inputs_2d new file mode 100644 index 000000000..5f4aafce5 --- /dev/null +++ b/Examples/Tests/RepellingParticles/inputs_2d @@ -0,0 +1,53 @@ +max_step = 200 +amr.n_cell = 128 128 + +amr.blocking_factor = 16 +amr.max_grid_size = 1024 +amr.max_level = 0 + +# Geometry +geometry.coord_sys = 0 # 0: Cartesian +geometry.prob_lo = -32.e-6 -32.e-6 # physical domain +geometry.prob_hi = 32.e-6 32.e-6 + +# Boundary condition +boundary.field_lo = pec pec +boundary.field_hi = pec pec + +# Algorithms +algo.current_deposition = esirkepov +algo.field_gathering = momentum-conserving +algo.charge_deposition = standard +algo.particle_pusher = vay +algo.maxwell_solver = yee +warpx.cfl = 0.9 +warpx.use_filter = 0 +warpx.do_dive_cleaning = 1 + +# Particle species +particles.species_names = electron1 electron2 + +electron1.charge = q_e +electron1.mass = m_e +electron1.injection_style = "singleparticle" +electron1.single_particle_pos = 1.e-6 0. 0. +electron1.single_particle_vel = 0. 0. 0. +electron1.single_particle_weight = 5.e12 +electron1.initialize_self_fields = 1 + +electron2.charge = q_e +electron2.mass = m_e +electron2.injection_style = "singleparticle" +electron2.single_particle_pos = -1.e-6 0. 0. +electron2.single_particle_vel = 0. 0. 0. +electron2.single_particle_weight = 5.e12 +electron2.initialize_self_fields = 1 + +# Order of particle shape factors +algo.particle_shape = 3 + +# Diagnostics +diagnostics.diags_names = diag1 +diag1.intervals = 20 +diag1.diag_type = Full +diag1.fields_to_plot = Bx By Bz Ex Ey Ez jx jy jz divE rho F diff --git a/Regression/Checksum/benchmarks_json/RepellingParticles.json b/Regression/Checksum/benchmarks_json/RepellingParticles.json new file mode 100644 index 000000000..03ef682f1 --- /dev/null +++ b/Regression/Checksum/benchmarks_json/RepellingParticles.json @@ -0,0 +1,36 @@ +{ + "electron1": { + "particle_cpu": 0.0, + "particle_id": 1.0, + "particle_momentum_x": 7.290949775645051e-23, + "particle_momentum_y": 0.0, + "particle_momentum_z": 1.513278897057852e-34, + "particle_position_x": 1.2979353623843636e-05, + "particle_position_y": 2.5918801452693848e-17, + "particle_weight": 5000000000000.0 + }, + "electron2": { + "particle_cpu": 0.0, + "particle_id": 2.0, + "particle_momentum_x": 7.290949775607332e-23, + "particle_momentum_y": 0.0, + "particle_momentum_z": 5.946822451302689e-36, + "particle_position_x": 1.2979353623849498e-05, + "particle_position_y": 1.965966968442628e-17, + "particle_weight": 5000000000000.0 + }, + "lev=0": { + "Bx": 0.0, + "By": 10242.068161511446, + "Bz": 0.0, + "Ex": 11293464466157.39, + "Ey": 0.0, + "Ez": 15385290305753.018, + "F": 8593.555096981512, + "divE": 1.709174685907196e+18, + "jx": 495250727461219.1, + "jy": 0.0, + "jz": 564.3956467573765, + "rho": 6408706.535999998 + } +}
\ No newline at end of file diff --git a/Regression/WarpX-tests.ini b/Regression/WarpX-tests.ini index 2a5d38b94..a5f3e4fb1 100644 --- a/Regression/WarpX-tests.ini +++ b/Regression/WarpX-tests.ini @@ -1593,6 +1593,22 @@ doVis = 0 analysisRoutine = Examples/analysis_default_regression.py tolerance = 1.e-14 +[RepellingParticles] +buildDir = . +inputFile = Examples/Tests/RepellingParticles/inputs_2d +runtime_params = +dim = 2 +addToCompileString = +restartTest = 0 +useMPI = 1 +numprocs = 2 +useOMP = 1 +numthreads = 2 +compileTest = 0 +doVis = 0 +analysisRoutine = Examples/Tests/RepellingParticles/analysis_repelling.py +tolerance = 1.e-14 + [Larmor] buildDir = . inputFile = Examples/Tests/Larmor/inputs_2d_mr |