Author:

Keywords:

atomic processes, shock waves, Sun: chromosphere, Sun: magnetic fields, Sun: oscillations, Science & Technology, Physical Sciences, Astronomy & Astrophysics, IONIZED 2-FLUID PLASMA, FINITE-VOLUME SOLVER, TRANSITION REGION, MAGNETOHYDRODYNAMIC SIMULATIONS, NUMERICAL SIMULATIONS, UNSTRUCTURED MESHES, ALFVEN WAVES, COEFFICIENTS, EQUILIBRIUM, PREDICTION, astro-ph.SR, physics.plasm-ph, 0201 Astronomical and Space Sciences, 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics, 0306 Physical Chemistry (incl. Structural), 5101 Astronomical sciences, 5107 Particle and high energy physics, 5109 Space sciences

Abstract:

© 2017. The American Astronomical Society. All rights reserved. In order to study chromospheric magnetosonic wave propagation including, for the first time, the effects of ion-neutral interactions in the partially ionized solar chromosphere, we have developed a new multi-fluid computational model accounting for ionization and recombination reactions in gravitationally stratified magnetized collisional media. The two-fluid model used in our 2D numerical simulations treats neutrals as a separate fluid and considers charged species (electrons and ions) within the resistive MHD approach with Coulomb collisions and anisotropic heat flux determined by Braginskiis transport coefficients. The electromagnetic fields are evolved according to the full Maxwell equations and the solenoidality of the magnetic field is enforced with a hyperbolic divergence-cleaning scheme. The initial density and temperature profiles are similar to VAL III chromospheric model in which dynamical, thermal, and chemical equilibrium are considered to ensure comparison to existing MHD models and avoid artificial numerical heating. In this initial setup we include simple homogeneous flux tube magnetic field configuration and an external photospheric velocity driver to simulate the propagation of MHD waves in the partially ionized reactive chromosphere. In particular, we investigate the loss of chemical equilibrium and the plasma heating related to the steepening of fast magnetosonic wave fronts in the gravitationally stratified medium.