diffusion.in

# AthenaPK - a performance portable block structured AMR MHD code
# Copyright (c) 2021-2024, Athena Parthenon Collaboration. All rights reserved.
# Licensed under the BSD 3-Clause License (the "LICENSE");

<comment>
problem   = Diffusion setup (for thermal, momentum and Ohmic diffusion tests)

<job>
problem_id = diffusion

<problem/diffusion>
#iprob = 0    # Diffusion of step function in x1 direction; 1 for x2 direction; 2 for x3
Bx = 1.0     # Bx for x1 step function (permutated for iprobs in other directions)
By = 0.0     # By for x1 step function (permutated for iprobs in other directions)

#iprob = 10   # Diffusion of Gaussian profile in x1 direction
t0 = 0.5      # Temporal offset for initial Gaussian profile
amp = 1e-6    # Amplitude of Gaussian profile

iprob = 20   # ring diffusion in x1-x2 plane; 21 for x2-x3 plane; 22 for x3-x1 plane

<parthenon/mesh>
refinement = none
nghost = 2

nx1 = 128
x1min = -1.0
x1max = 1.0
ix1_bc = periodic
ox1_bc = periodic

nx2 = 128
x2min = -1.0
x2max = 1.0
ix2_bc = periodic
ox2_bc = periodic

nx3 = 1
x3min = -1.0
x3max = 1.0
ix3_bc = periodic
ox3_bc = periodic

<parthenon/meshblock>
nx1=64
nx2=64 
nx3=1

<parthenon/time>
integrator = rk1
cfl = 0.3
tlim = 10.0
nlim = 1000000

<hydro>
fluid = glmmhd
riemann = none
eos = adiabatic
reconstruction = dc
gamma = 2.0

<diffusion>
integrator = rkl2
conduction = anisotropic
conduction_coeff = fixed
thermal_diff_coeff_code = 0.01
viscosity = none            # none (disabled), isotropic, or anisotropic
viscosity_coeff = fixed
mom_diff_coeff_code = 0.25
resistivity = none          # none (disabled) or ohmic
resistivity_coeff = fixed
ohm_diff_coeff_code = 0.25
rkl2_max_dt_ratio = 100.0

<parthenon/output0>
file_type = hdf5
dt = 10.0
variables = prim
id = prim