Two-fluid Modeling of Acoustic Wave Propagation in Gravitationally Stratified Isothermal Media
arXiv:2011.13469 · doi:10.3847/1538-4357/abe7e8
Abstract
To study acoustic wave propagation and the corresponding energy deposition in partially ionized plasmas, we use a two-fluid computational model that treats neutrals and charged particles (electrons and ions) as two separate fluids. This two-fluid model takes into account the ion-neutral collisions, ionization, and recombination, allowing us to investigate both the collisional and reactive interactions between uncoupled ions and neutrals in the plasmas. In the present numerical simulations, the initial density is specified to reach hydrostatic equilibrium, and as a comparison, chemical equilibrium is also taken into account to provide a density profile that differs from typical hydrostatic equilibrium profiles. External velocity drivers are then imposed to generate monochromatic acoustic waves. As is well known, the upward propagating acoustic waves steepen in gravitationally stratified plasmas due to the exponentially decreasing density, and they heat the plasmas in the nonlinear regimes where kinetic energy is dissipated by shock waves and collisional interactions. In particular, the lower ionization fraction resulting from the present initial chemical equilibrium significantly enhances the heating efficiency. Moreover, the ionization process absorbs a significant amount of energy, and the decoupling between ions and neutrals is also enhanced while considering ionization and recombination. Therefore, simulations without considering ionization and recombination may overestimate the overall heating effects but also underestimate the energy dissipation. The results also suggest that a more accurate ionization and recombination model could be essential for improving the modeling of partially ionized plasmas.
24 pages, 16 figures
References in corpus (14)
- Non-equilibrium hydrogen ionization in 2D simulations of the solar atmosphere
- Fluid description of multi-component solar partially ionized plasma
- Ion-neutral interactions and non-equilibrium ionization in the solar chromosphere
- Overdamped Alfven waves due to ion-neutral collisions in the solar chromosphere
- Multifluid modeling of magnetosonic wave propagation in the solar chromosphere -- effects of impact ionization and radiative recombination
- Asymmetric Magnetic Reconnection in Weakly Ionized Chromospheric Plasmas
- Nonequilibrium ionization and ambipolar diffusion in solar magnetic flux emergence processes
- On the effects of ion-neutral interactions in solar plasmas
- Multi-fluid Approach to High-frequency Waves in Plasmas. II. Small-amplitude Regime in Partially Ionized Media
- Two-fluid numerical simulations of solar spicules
- Generation of electric currents in the chromosphere via neutral-ion drag
- Heating of a Quiet Region of the Solar Chromosphere by Ion and Neutral Acoustic Waves
- Effects of Cowling Resistivity in the Weakly-Ionized Chromosphere
- Slow magnetoacoustic waves in gravitationally stratified two-fluid plasmas in strongly ionised limit