def init(self, kw):
# --- When using the PICMI standard, always make the particles
# --- have variable weights. This will greatly simplify the
# --- handling of particle initialization. The species weight
# --- will be set to 1, and the variable weight will hold
# --- the actual weight.
wtype = species_type_dict.get(self.particle_type, None)
self.wspecies = warp.Species(type = wtype,
name = self.name,
charge = self.charge,
charge_state = self.charge_state,
mass = self.mass,
lvariableweights = True,
weight = 1.)
# --- Setup the description text which will be included at the bottom # --- of every plot frame. This is for user convenience, documenting # --- what the simulation is on the graphical output. wp.top.pline2 = "Example 3D beam in a FODO lattice" wp.top.pline1 = "Semi-Gaussian cigar beam. 32x32x128" wp.top.runmaker = "David P. Grote" # --- Invoke plotting setup routine - it is needed to create a cgm output file for plots. # --- The plot file will have a name with the format FODO3D.###.cgm. The prefix is the # --- same as the input file name, and the ### is a number, increasing each time the # --- simulation is carried out. wp.setup() # --- Create the beam species. This instance of the Species class # --- is used to configure aspects related to the beam and particles. beam = wp.Species(type=wp.Potassium, charge_state=+1, name="Beam species") # --- Set input parameters describing the beam, with a tune depression of 72 to 20 degrees. # --- These numbers were generated by hand, by using the env package and adjusting the # --- parameters to get the desired results. # --- Note the units multipliers, e.g. mm. Almost all variables are MKS units # --- (except ekin). The multipliers provide a nice way of converting to MKS # --- while providing documentation about the units that are being used. beam.a0 = 8.760439903086566 * wp.mm beam.b0 = 15.599886448447793 * wp.mm beam.emit = 6.247186343204832e-05 beam.ap0 = 0. beam.bp0 = 0. beam.ibeam = 2. * wp.mA beam.vbeam = 0. beam.ekin = 80. * wp.kV
def warp_species(warp_type, picmi_species, level=0):
"""Returns a Warp species that has a reference to the WarpX particles.
"""
pgroups = PGroup.PGroups(ispecie=picmi_species.species_number, level=level)
return warp.Species(type=warp_type, pgroups=pgroups)
diode_voltage = 93. * wp.kV
# --- Setup source plate
source_radius = 5.5 * wp.cm
source_temperature = 0.1 # in eV
source_curvature_radius = 30. * wp.cm # --- radius of curvature of emitting surface
pierce_angle = 67.
# --- Setup diode aperture plate
zplate = 8. * wp.cm # --- plate location
rplate = 5.5 * wp.cm # --- aperture radius
plate_width = 2.5 * wp.cm # --- thickness of aperture plate
# --- Setup simulation species
beam = wp.Species(type=wp.Potassium, charge_state=+1, name='beam')
# --- Child-Langmuir current between parallel plates
j = 4. / 9. * wp.eps0 * wp.sqrt(2. * wp.echarge * beam.charge_state /
beam.mass) * diode_voltage**1.5 / zplate**2
diode_current = wp.pi * source_radius**2 * j
print("Child-Langmuir current density = ", j)
print("Child-Langmuir current = ", diode_current)
# --- Set basic beam parameters
beam.a0 = source_radius
beam.b0 = source_radius
beam.ap0 = .0e0
beam.bp0 = .0e0
beam.ibeam = diode_current
####################################
# Create Beam and Set its Parameters
####################################
# parameters for electron beam:
# total energy: 3.2676813658 MeV
# beta_e: 0.990813945176
wp.top.lrelativ = True
wp.top.relativity = True
ptcl_per_step = 400 # number of particles to inject on each step
wp.top.npinject = ptcl_per_step
beam = wp.Species(type=wp.Electron,
name='Electron',
lvariableweights=variable_weight)
if space_charge:
beam.ibeam = beam_current
else:
beam.ibeam = 0.0
wp.w3d.l_inj_exact = True # if true, position and angle of injected particle are
# computed analytically rather than interpolated
"""
A custom injector routine is used here to allow for a very relativistic beam to be injected directly into the simulation
because Warp's built in routine is not based on relativistic kinematics. Setting user_injection = False should work
well for lower energy beams.
"""
if user_injection:
def warp_species(warp_type, picmie_species):
"""Returns a Warp species that has a reference to the WarpX particles.
"""
elec_pgroups = PGroup.PGroups(ispecie=picmie_species.species_number)
return warp.Species(type=warp_type, pgroups=elec_pgroups)
####################################
# Create Beam and Set its Parameters
####################################
# parameters for electron beam:
# total energy: 3.2676813658 MeV
# beta_e: 0.990813945176
wp.top.lrelativ = True
wp.top.relativity = True
ptcl_per_step = 400 # number of particles to inject on each step
wp.top.npinject = ptcl_per_step
beam = wp.Species(type=wp.Electron,
name='Electron',
lvariableweights=variable_weight)
if space_charge:
beam.ibeam = beam_current
else:
beam.ibeam = 0.0
wp.w3d.l_inj_exact = True # if true, position and angle of injected particle are
# computed analytically rather than interpolated
"""
A custom injector routine is used here to allow for a very relativistic beam to be injected directly into the simulation
because Warp's built in routine is not based on relativistic kinematics. Setting user_injection = False should work
well for lower energy beams.
"""
if user_injection: