During my testing, I encountered the following message after the simulation completed:
"Note: The following floating-point exceptions are signalling: IEEE_INVALID_FLAG."
I have enabled QED and Bremsstrahlung radiation in the Makefile. Could this have an impact on my results? Below is my input program.
begin:control
nx = 2500
ny = 350
nz = 350
t_end = 200 * femto
x_min = 0
x_max = 50*micron
y_min = -7*micron
y_max = 7*micron
dt_multiplier = 0.8
# dlb_threshold = 0.8
# field_order = 2
# maxwell_solver = yee
# restart_snapshot = 98
stdout_frequency = 10
end:control
begin:boundaries
bc_x_min = simple_laser
bc_x_max = simple_outflow
bc_y_min = open
bc_y_max = open
end:boundaries
begin:constant
lambda0 = 0.8 * micron
w_0 = 3 * micron
r = sqrt(y^2)
k = 2.0 * pi / lambda0
n_c = 1.7e27
n_e = 25*n_c
R_0 = sqrt(y^2)
r_x = (1/30)*x+0.4*micron
wo=7* micron
x0=40* micron+2* micron*exp-((y^2)/wo^2)
end:constant
begin:laser
boundary = x_min
intensity_w_cm2 = 4.51e22
lambda = lambda0
pol_angle = pi/2
profile = gauss(time, 24*femto, 12*femto)
t_profile = gauss(time, 24*femto, 12*femto)
phase = pi/2
end:laser
begin:laser
boundary = x_min
intensity_w_cm2 = 4.51e22
lambda = lambda0
pol_angle = pi/2
t_profile = gauss(time, 24*femto, 12*femto)
profile = gauss(time, 24*femto, 12*femto)
phase = 0
end:laser
begin:qed
# These are the parts that control the QED sections of EPOCH
use_qed = T # Turn on or off QED. If you're normally running without QED then
# don't compile with -DPHOTONS
qed_start_time = 0 # Time after which QED effects should start.
produce_photons = T # Should the code actually produce and track photons.
# If F then the code calculates the recoil due to emitting
# photons, but the photon is not tracked. qed must be on
# to Ever produce photons
photon_energy_min = 1 * mev # Minimum energy for a tracked photon. Photons
# emitted with lower energy still cause electron
# recoil but are not tracked
produce_pairs = F # Whether or not to activate the module for pair production
# by the Breit-Wheeler process. Both qed and
# produce_photons must be on to produce pairs
photon_dynamics = T # Quite often you're more interested in where photons are
# generated than where they propagate to. This option
# stops the core code from moving the photons.
# This is also much faster.
use_radiation_reaction = T
end:qed
begin:species
name = electron
charge = -1.0
mass = 1.0
number_density = if((x gt 3*micron) and (x lt 18*micron) and (R_0 lt r_x), n_e, 0)
number_density = if((x gt x0) and (x lt 44*micron),555*n_c,number_density(electron))
npart_per_cell = 1
identify:electron
end:species
begin:species
name = Aluminium
charge = 5.0
mass = 1837*27
number_density = if((x gt x0) and (x lt 44*micron),111*n_c,0)
npart_per_cell = 1
immobile=T
identify:electron
end:species
begin:species
name = proton
mass = 1836
number_density = if((x gt 3*micron) and (x lt 18*micron) and (R_0 lt r_x), n_e, 0)
charge = 1
npart_per_cell = 1
identify:proton
end:species
begin:species
name = photon
nparticles = 0 # nparticles=0 since there are no initial photons in the system
dump = T
# This is the key line here. It identifies that this species is a photon
# species. Without this line this species won't work properly. Presently you
# can't specify initial conditions for photons.
identify:photon
end:species
begin:species
name = positron
nparticles = 0 # nparticles=0 since no initial positrons in the system
dump = T
# This identifies this species as a positron. In most senses it's still a
# normal charged particle species. You can specify initial conditions as
# normal. If you identify multiple species as positrons then the QED routines
# will produce the positrons from pairs in the first specified positron
# species. If you want to specify which positron species should receive pair
# positrons then identify it using identify:breit_wheeler_positron
identify:positron
end:species
begin:output
name = number_density
file_prefix = number_density
number_density = always + species + single + no_sum
dt_snapshot = 3*femto
time_start = 0*femto
end:output
begin:output
name = dist_fn
file_prefix = dist_fn
dt_snapshot = 1* femto
distribution_functions = always
end:output
begin:dist_fn
name = en
ndims = 1
dumpmask = always
direction1 = dir_en
range1 = (0,2000*mev)
resolution1 = 1000
include_species: electron
end:dist_fn
begin:dist_fn
name = en
ndims = 1
dumpmask = always
direction1 = dir_en
range1 = (0,500*mev)
resolution1 = 1000
include_species: photon
end:dist_fn
begin:output
name = total_energy_sum
file_prefix = total_energy_sum
total_energy_sum = always + single + species + no_sum
dt_snapshot = 1*femto
end:output
Dear Professor,
During my testing, I encountered the following message after the simulation completed: "Note: The following floating-point exceptions are signalling: IEEE_INVALID_FLAG."
I have enabled QED and Bremsstrahlung radiation in the Makefile. Could this have an impact on my results? Below is my input program.