The effect of flow on resonant absorption of slow MHD waves in magnetic flux tubes

TL;DR

This study investigates how plasma flow influences the resonant absorption and damping of slow MHD waves in magnetic flux tubes, explaining rapid damping observed in magnetic pores.

Contribution

It provides a numerical and analytical analysis of wave damping due to flow effects, highlighting the role of resonance absorption in magnetic pore conditions.

Findings

Flow enhances damping of forward waves via resonance absorption.

Flow reduces damping efficiency for backward waves.

Resonance instability is avoided in the model for pore conditions.

Abstract

In this paper, we study kink and sausage oscillations in the presence of longitudinal background flow. We study resonant absorption of the kink and sausage modes in the slow continuum under magnetic pore conditions in the presence of flow. we determine the dispersion relation then solve it numerically, and find the frequencies and damping rates of the slow kink and sausage surface modes. We also, obtain analytical solution for the damping rate of the slow surface mode in the long wavelength limit. We show that in the presence of plasma flow, resonance absorption can result in strong damping for forward waves and can be considered as an efficient mechanism to justify the extremely rapid damping of slow surface sausage waves observed in magnetic pores. Also, the plasma flow reduces the efficiency of resonance absorption to damp backward waves. Furthermore, for the pore conditions, the resonance instability is avoided in our model.