mod_physics_vars_mhd.f90 Source File

module mod_physics_vars_mhd
  use mod_global_parameters, only: name_len, ndim

  implicit none
  public
  
  double precision :: phys_gamma=5.d0/3.d0
  

  !> String describing the physics type of the simulation
  character(len=name_len) :: physics_type = "mhd"
  

  !> To use wider stencils in flux calculations. A value of 1 will extend it by
  !> one cell in both directions, in any dimension
  integer :: phys_wider_stencil = 0
  

  !> Array per direction per variable, which can be used to specify that certain
  !> fluxes have to be treated differently
  integer, allocatable :: flux_type(:, :)
  

  !> Indicates a normal flux
  integer, parameter   :: flux_default        = 0
  !> Indicates the flux should be treated with tvdlf
  integer, parameter   :: flux_tvdlf          = 1
  
  !> Whether the physics routines require diagonal ghost cells, for example for
  !> computing a curl.
  logical :: phys_req_diagonal = .true.
  

  !> Solve energy equation or not
  logical :: phys_energy=.false.
  
  
  !> Solve total energy equation or not
  logical :: phys_total_energy=.false.
  

  !> Solve internal energy instead of total energy
  logical :: phys_internal_e=.false.
  

  !> Solve partially ionized one-fluid plasma
  logical :: phys_partial_ionization=.false.
  

  !> if equilibrium pressure is splitted
  logical :: phys_equi_pe=.false.
  


  integer, parameter :: dp = kind(0.0d0)
  integer, parameter, public              :: nw_phys=2+2*ndim+1+1 &
    + ndim

  integer, parameter, public              :: nw_flux=2+2*ndim+1+1 &
    + ndim

  !> Whether an energy equation is used
  logical, public                         :: mhd_energy = .true.
  

  !> Index of the density (in the w array)
  integer, public                         :: rho_
  

  !> Indices of the momentum density
  integer, allocatable, public            :: mom(:)
  

  !> Indices of the tracers
  integer, public                         :: tracer(1)
  

  !> Index of the energy density (-1 if not present)
  integer, public                         :: e_
  

  !> Indices of the magnetic field
  integer, allocatable, public            :: mag(:)
  

  !> Index of the gas pressure (-1 if not present) should equal e_
  integer, public                         :: p_
  

  !> Indices of the GLM psi
  integer, public :: psi_
  

  !> Number of tracer species
  integer, public                         :: mhd_n_tracer = 0
  

  !> The adiabatic index
  double precision, public                :: mhd_gamma = 5.d0/3.0d0
  double precision, public                :: gamma_1, inv_gamma_1
  
  

  !> Helium abundance over Hydrogen
  double precision, public  :: He_abundance=0.1d0
  
  !> Ionization fraction of H
  !> H_ion_fr = H+/(H+ + H)
  double precision, public  :: H_ion_fr=1d0
  
  !> Ionization fraction of He
  !> He_ion_fr = (He2+ + He+)/(He2+ + He+ + He)
  double precision, public  :: He_ion_fr=1d0
  
  !> Ratio of number He2+ / number He+ + He2+
  !> He_ion_fr2 = He2+/(He2+ + He+)
  double precision, public  :: He_ion_fr2=1d0
  
  ! used for eq of state when it is not defined by units,
  ! the units do not contain terms related to ionization fraction
  ! and it is p = RR * rho * T
  double precision, public  :: RR=1d0
  

  !> Switch for hyperbolic thermal conduction
  logical, public                         :: mhd_hyperbolic_thermal_conduction = .false.
  

  !> Compile-time selector for anisotropic HTC
  logical, public                         :: mhd_hyperbolic_thermal_conduction_anisotropic = .false.

  !> Freeze rho/v/B and evolve only the energy equation (compile-time MHD_ENERGY_ONLY flag)
  logical, public                         :: mhd_energy_only = .false.

  !> sig_par = tc_kappa_par (constant, no T^2.5); takes precedence over tc_kappa0_par when > 0
  double precision, public                :: tc_kappa_par = -1.0d0
  

  !> sig_perp = tc_kappa_perp (constant, no T^2.5); takes precedence over the Braginskii closure when > 0
  double precision, public                :: tc_kappa_perp = -1.0d0
  

  ! HYPERTC_ANISO implies HYPERTC (enforced in config_schema.toml)
  !> sig_par = tc_kappa0_par * Te^2.5; if <= 0 and tc_kappa_par <= 0, set from Spitzer in phys_units()
  double precision, public                :: tc_kappa0_par = -1.0d0
  

  !> Indices of the heat-flux vector components q_(1:ndir); this is the full Cartesian heat-flux vector
  integer, allocatable, public            :: q_(:)
  

  !> Magnetisation chi prefactor: chi = htc_Cchi * B * Te^1.5 / n
  double precision, public                :: htc_Cchi = 0.0d0
  

  !> GLM-MHD parameter: ratio of the diffusive and advective time scales for div b
  !> taking values within [0, 1]
  double precision, public                :: mhd_glm_alpha = 0.5d0
  

  !> Whether to use gravity
  logical, public                         :: mhd_gravity = .false.
  

  !> The resistivity
  double precision, public                :: mhd_eta = 0.0d0
  

  !> switch for adding resistive terms
  logical, public                         :: mhd_resistivity = .false.
  

  !> Whether plasma is partially ionized
  logical, public                         :: mhd_partial_ionization = .false.
  

  !> switch for radiative cooling
  logical, public                         :: mhd_radiative_cooling = .false.
  

  !> Whether particles module is added
  logical, public                         :: mhd_particles = .false.
  

  !> switch for source user
  logical, public                         :: mhd_source_usr = .false.
  


end module mod_physics_vars_mhd