3D numerical simulations of propagating two-fluid, torsional Alfv\'en waves and heating of a partially-ionized solar chromosphere

TL;DR

This paper uses 3D numerical simulations of two-fluid torsional Alfvén waves in the partially-ionized solar chromosphere to explore their propagation, dissipation, and potential role in heating the lower solar atmosphere.

Contribution

It introduces a novel 3D two-fluid simulation approach to study Alfvén wave dynamics and heating in the partially-ionized chromosphere, highlighting ion-neutral interactions.

Findings

Significant plasma heating along magnetic flux-tubes due to wave dissipation.

Ion-neutral drift increases with height, enhancing wave damping.

Two-fluid effects are crucial for understanding chromospheric heating.

Abstract

We present a new insight into the propagation, attenuation and dissipation of two-fluid, torsional Alfv\'en waves in the context of heating of the lower solar atmosphere. By means of numerical simulations of the partially-ionized plasma, we solve the set of two-fluid equations for ion plus electron and neutral fluids in three-dimensional (3D) Cartesian geometry. We implement initially a current-free magnetic field configuration, corresponding to a magnetic flux-tube that is rooted in the solar photosphere and expands into the chromosphere and corona. We put the lower boundary of our simulation region in the low chromosphere, where ions and neutrals begin to decouple, and implement there a monochromatic driver that directly generates Alfv\'en waves with a wave period of 30 s. As the ion-neutral drift increases with height, the two-fluid effects become more significant and the energy carried by both Alfv\'en and magneto-acoustic waves can be thermalized in the process of ion-neutral collisions there. In fact, we observe a significant increase in plasma temperature along the magnetic flux-tube. In conclusion, the two-fluid torsional Alfv\'en waves can potentially play a role in the heating of the solar chromosphere.