# Wave modes excited by photospheric p-modes and mode conversion in a multi-loop system

## TL;DR

This study investigates how photospheric p-modes excite various wave modes in coronal loops, revealing mode conversion processes and quantifying the conversion efficiency across different magnetic inclinations.

## Contribution

It introduces 3D MHD simulations of multi-loop systems to analyze wave excitation and mode conversion, providing new insights into wave behavior in the lower solar corona.

## Key findings

- Deformed fast sausage surface waves are excited in vertical flux tubes.
- Inclined flux tubes excite kink and sausage body waves.
- The wave conversion factor varies with magnetic inclination, matching theoretical predictions within 40%.

## Abstract

Context. Waves are ubiquitous in the solar corona and there are indications that they are excited by photospheric p-modes. However, it is unclear how p-modes in coronal loops are converted to sausage modes and transverse (kink) modes, which are observed in the corona. Aims. We aim to investigate how those wave modes are excited in the lower corona by photospheric acoustic waves. Methods. We built 3D magnetohydrostatic loop systems with multiple inclinations spanning from the photosphere to the lower corona. We then simulated these atmospheres with the MANCHA code, in which we perturb the equilibrium with a p-mode driver at the bottom of the domain. By splitting the velocity perturbation into components longitudinal, normal, and azimuthal to the magnetic flux surfaces we can study wave behavior. Results. In vertical flux tubes, we find that deformed fast sausage surface waves and slow sausage body waves are excited. In inclined flux tubes fast kink surface waves, slow sausage body waves, and either a fast sausage surface wave or a plane wave are excited. In addition, we calculate a wave conversion factor (0 $\le$ C $\le$ 1) from acoustic to magnetic wave behavior by taking the ratio of the mean magnetic energy flux to the sum of the mean magnetic and acoustic energy flux and compare it to a commonly used theoretical conversion factor. We find that between magnetic field inclinations of 10$^\circ$ to 30$^\circ$ those two methods lie within 40%. For smaller inclinations the absolute deviation is smaller than 0.1.