nz = 256
# Physical domain
zmin = -56e-06
zmax = 12e-06
# Domain decomposition
max_grid_size = 64
blocking_factor = 32
# Create grid
grid = picmi.Cartesian1DGrid(number_of_cells=[nz],
lower_bound=[zmin],
upper_bound=[zmax],
lower_boundary_conditions=['dirichlet'],
upper_boundary_conditions=['dirichlet'],
lower_boundary_conditions_particles=['absorbing'],
upper_boundary_conditions_particles=['absorbing'],
moving_window_velocity=[c],
warpx_max_grid_size=max_grid_size,
warpx_blocking_factor=blocking_factor)
# Particles: plasma electrons
plasma_density = 2e23
plasma_xmin = None
plasma_ymin = None
plasma_zmin = 10e-06
plasma_xmax = None
plasma_ymax = None
plasma_zmax = None
uniform_distribution = picmi.UniformDistribution(
density=plasma_density,
def setup_run(self):
"""Setup simulation components."""
#######################################################################
# Set geometry and boundary conditions #
#######################################################################
self.grid = picmi.Cartesian1DGrid(
number_of_cells=[self.nz],
warpx_max_grid_size=128,
lower_bound=[0],
upper_bound=[self.gap],
lower_boundary_conditions=['dirichlet'],
upper_boundary_conditions=['dirichlet'],
lower_boundary_conditions_particles=['absorbing'],
upper_boundary_conditions_particles=['absorbing'],
warpx_potential_hi_z=self.voltage,
)
#######################################################################
# Field solver #
#######################################################################
self.solver = picmi.ElectrostaticSolver(grid=self.grid,
method='Multigrid',
required_precision=1e-12,
warpx_self_fields_verbosity=0)
#######################################################################
# Particle types setup #
#######################################################################
self.electrons = picmi.Species(
particle_type='electron',
name='electrons',
initial_distribution=picmi.UniformDistribution(
density=self.plasma_density,
rms_velocity=[
np.sqrt(constants.kb * self.elec_temp / constants.m_e)
] * 3,
))
self.ions = picmi.Species(
particle_type='He',
name='he_ions',
charge='q_e',
mass=self.m_ion,
initial_distribution=picmi.UniformDistribution(
density=self.plasma_density,
rms_velocity=[
np.sqrt(constants.kb * self.gas_temp / self.m_ion)
] * 3,
))
#######################################################################
# Collision initialization #
#######################################################################
cross_sec_direc = '../../../../warpx-data/MCC_cross_sections/He/'
mcc_electrons = picmi.MCCCollisions(
name='coll_elec',
species=self.electrons,
background_density=self.gas_density,
background_temperature=self.gas_temp,
background_mass=self.ions.mass,
scattering_processes={
'elastic': {
'cross_section':
cross_sec_direc + 'electron_scattering.dat'
},
'excitation1': {
'cross_section': cross_sec_direc + 'excitation_1.dat',
'energy': 19.82
},
'excitation2': {
'cross_section': cross_sec_direc + 'excitation_2.dat',
'energy': 20.61
},
'ionization': {
'cross_section': cross_sec_direc + 'ionization.dat',
'energy': 24.55,
'species': self.ions
},
})
mcc_ions = picmi.MCCCollisions(
name='coll_ion',
species=self.ions,
background_density=self.gas_density,
background_temperature=self.gas_temp,
scattering_processes={
'elastic': {
'cross_section': cross_sec_direc + 'ion_scattering.dat'
},
'back': {
'cross_section': cross_sec_direc + 'ion_back_scatter.dat'
},
# 'charge_exchange' : {
# 'cross_section' : cross_sec_direc+'charge_exchange.dat'
# }
})
#######################################################################
# Initialize simulation #
#######################################################################
self.sim = picmi.Simulation(
solver=self.solver,
time_step_size=self.dt,
max_steps=self.max_steps,
warpx_collisions=[mcc_electrons, mcc_ions],
warpx_load_balance_intervals=self.max_steps // 5000,
verbose=self.test)
self.sim.add_species(self.electrons,
layout=picmi.GriddedLayout(
n_macroparticle_per_cell=[self.seed_nppc],
grid=self.grid))
self.sim.add_species(self.ions,
layout=picmi.GriddedLayout(
n_macroparticle_per_cell=[self.seed_nppc],
grid=self.grid))
#######################################################################
# Add diagnostics for the CI test to be happy #
#######################################################################
field_diag = picmi.FieldDiagnostic(
name='diag1',
grid=self.grid,
period=0,
data_list=['rho_electrons', 'rho_he_ions'],
write_dir='.',
warpx_file_prefix='Python_background_mcc_1d_plt')
self.sim.add_diagnostic(field_diag)