Numerical Simulations of Two-Fluid Magnetoacoustic Waves in the Solar Atmosphere

TL;DR

This study uses numerical simulations of a two-fluid model to analyze magnetoacoustic wave periods and cutoff phenomena in the partially ionized lower solar atmosphere, revealing their influence on wave propagation to the corona.

Contribution

It introduces a 1D two-fluid simulation approach to investigate wave cutoff effects and their role in solar atmospheric wave propagation, a novel perspective in solar physics.

Findings

Wave-period cutoffs are identified and characterized.

Some waves can propagate from the photosphere to the corona.

Wave cutoffs influence energy transfer in the solar atmosphere.

Abstract

We study vertical variations of wave-periods of magnetoacoustic two-fluid waves in the partially ionized lower solar atmosphere, consisting of ion (proton) + electron and neutral (atomic hydrogen) fluids, which are coupled by ion-neutral collisions. The study allows finding the wave period cutoffs and their variations in the solar atmosphere, as well as establishing the role of these cutoffs in determining the wave propagation conditions. The atmosphere is permitted by a uniform vertical magnetic field. We perform numerical simulations in the framework of a one-dimensional (1D), two-fluid model in which plane waves are exited by a harmonic driver in the vertical ion and neutral velocities, operating at the bottom of the solar photosphere. We observe excitation of waves with cutoff wave-periods in addition to waves set directly by the driver. We also see that some waves exited by that driver can reach the solar corona. Despite of its limitations such as the lack of non-adiabatic and non-ideal terms and a simple 1D structure, the developed two-fluid model of the solar atmosphere sheds a new light on the role of cutoffs in setting up the wave propagation conditions in the solar atmosphere and finding periods of waves that may carry their energy from the solar surface to the corona.