Driven two-fluid slow magnetoacoustic waves in the solar chromosphere with a realistic ionisation profile

¹ Institute of Physics, University of Maria Curie-Skłodowska, Pl. Marii Curie-Skłodowskiej 1, 20-031 Lublin, Poland
² Centre for mathematical Plasma Astrophysics / Department of Mathematics, KU Leuven, Celestijnenlaan 200B, 3001 Leuven, Belgium

^⋆ Corresponding author; robert.niedziela.96@gmail.com

Received: 11 March 2024
Accepted: 8 September 2024

Abstract

Context. This study was carried out in the context of chromosphere heating.

Aims. This paper aims to discuss the evolution of driven slow magnetoacoustic waves (SMAWs) in the solar chromosphere modelled with a realistic ionisation profile and to consider their potential role in plasma heating and the generation of plasma outflows.

Methods. Two-dimensional (2D) numerical simulations of the solar atmosphere are performed using the JOANNA code. The dynamic behaviour of the atmospheric plasma is governed by the two-fluid equations (with ionisation and recombination terms taken into account) for neutrals (hydrogen atoms) and ions (protons)+electrons. The initial atmosphere is described by a hydrostatic equilibrium (HE) supplemented by the Saha equation (SE) and embedded in a fanning magnetic field. This initial equilibrium is perturbed by a monochromatic driver which operates in the chromosphere on the vertical components of the ion and neutral velocities.

Results. Our work shows that the HE+SE model results in time-averaged (net) plasma outflows in the top chromosphere, which are larger than their pure HE counterpart. The parametric studies demonstrate that the largest chromosphere temperature rise occurs for smaller wave driving periods. The plasma outflows exhibit the opposite trend, growing with the driver period.

Conclusions. We find that the inclusion of the HE+SE plasma background plays a key role in the evolution of SMAWs in the solar atmosphere.