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#!/usr/bin/env python3
#
# --- Simple example of Langmuir oscillations in a uniform plasma
from pywarpx import picmi
constants = picmi.constants
##########################
# physics parameters
##########################
plasma_density = 1.e25
plasma_xmin = 0.
plasma_x_velocity = 0.1*constants.c
##########################
# numerics parameters
##########################
# --- Number of time steps
max_steps = 40
diagnostic_interval = 10
# --- Grid
nx = 64
ny = 64
nz = 64
xmin = -20.e-6
ymin = -20.e-6
zmin = -20.e-6
xmax = +20.e-6
ymax = +20.e-6
zmax = +20.e-6
number_per_cell_each_dim = [2,2,2]
##########################
# physics components
##########################
uniform_plasma = picmi.UniformDistribution(density = 1.e25,
upper_bound = [0., None, None],
directed_velocity = [0.1*constants.c, 0., 0.])
electrons = picmi.Species(particle_type='electron', name='electrons', initial_distribution=uniform_plasma)
##########################
# numerics components
##########################
grid = picmi.Cartesian3DGrid(number_of_cells = [nx, ny, nz],
lower_bound = [xmin, ymin, zmin],
upper_bound = [xmax, ymax, zmax],
lower_boundary_conditions = ['periodic', 'periodic', 'periodic'],
upper_boundary_conditions = ['periodic', 'periodic', 'periodic'],
moving_window_velocity = [0., 0., 0.],
warpx_max_grid_size = 32)
solver = picmi.ElectromagneticSolver(grid=grid, cfl=1.)
##########################
# diagnostics
##########################
field_diag1 = picmi.FieldDiagnostic(name = 'diag1',
grid = grid,
period = diagnostic_interval,
data_list = ['Ex', 'Jx'],
write_dir = '.',
warpx_file_prefix = 'Python_Langmuir_plt')
part_diag1 = picmi.ParticleDiagnostic(name = 'diag1',
period = diagnostic_interval,
species = [electrons],
data_list = ['weighting', 'ux'])
##########################
# simulation setup
##########################
sim = picmi.Simulation(solver = solver,
max_steps = max_steps,
verbose = 1,
warpx_current_deposition_algo = 'direct')
sim.add_species(electrons,
layout = picmi.GriddedLayout(n_macroparticle_per_cell=number_per_cell_each_dim, grid=grid))
sim.add_diagnostic(field_diag1)
sim.add_diagnostic(part_diag1)
##########################
# simulation run
##########################
# write_inputs will create an inputs file that can be used to run
# with the compiled version.
#sim.write_input_file(file_name = 'inputs_from_PICMI')
# Alternatively, sim.step will run WarpX, controlling it from Python
sim.step()
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