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Two-fluid simulations of waves in the solar chromosphere

Authors :
B. Popescu Braileanu
Vyacheslav S. Lukin
A. de Vicente
Elena Khomenko
Source :
Astronomy & Astrophysics. 630:A79
Publication Year :
2019
Publisher :
EDP Sciences, 2019.

Abstract

Waves and shocks traveling through the solar chromospheric plasma are influenced by its partial ionization and weak collisional coupling, and may become susceptible to multi-fluid effects, similar to interstellar shock waves. In this study, we consider fast magneto-acoustic shock wave formation and propagation in a stratified medium, that is permeated by a horizontal magnetic field, with properties similar to that of the solar chromosphere. The evolution of plasma and neutrals is modeled using a two-fluid code that evolves a set of coupled equations for two separate fluids. We observed that waves in neutrals and plasma, initially coupled at the upper photosphere, become uncoupled at higher heights in the chromosphere. This decoupling can be a consequence of either the characteristic spatial scale at the shock front, that becomes similar to the collisional scale, or the change in the relation between the wave frequency, ion cyclotron frequency, and the collisional frequency with height. The decoupling height is a sensitive function of the wave frequency, wave amplitude, and the magnetic field strength. We observed that decoupling causes damping of waves and an increase in the background temperature due to the frictional heating. The comparison between analytical and numerical results allows us to separate the role of the nonlinear effects from the linear ones on the decoupling and damping of waves.

Details

ISSN :
14320746 and 00046361
Volume :
630
Database :
OpenAIRE
Journal :
Astronomy & Astrophysics
Accession number :
edsair.doi.dedup.....f864e6f450d88730e5c5a264e7243923
Full Text :
https://doi.org/10.1051/0004-6361/201935844