On Modeling the Kelvin--Helmholtz Instability in Solar Atmosphere

TL;DR

This review discusses recent advances in modeling Kelvin-Helmholtz instability in solar MHD waves, especially in CMEs and jets, highlighting observational challenges and theoretical explanations for instability onset.

Contribution

It provides a comprehensive overview of modeling approaches for KH instability in solar structures, linking observations with theoretical MHD mode analysis.

Findings

KH instability explained by unstable m = -3 MHD mode in CMEs

Critical jet speeds for KH onset match observations

Linear wave growth rates align with high-resolution data

Abstract

In the present review article, we discuss the recent developments in studying the Kelvin--Helmholtz (KH) instability of magnetohydrodynamic (MHD) waves propagating in various solar magnetic structures. The main description is on the modeling of KH instability developing in the coronal mass ejections (CMEs), and contributes to the triggering of wave turbulence subsequently leading to the coronal heating. KH instability of MHD waves in coronal active regions recently observed and imaged in unprecedented detail in EUV high cadence, high-resolution observations by SDO/AIA, and spectroscopic observations by Hinode/EIS instrument, is posing now challenge for its realistic modeling. It is shown that considering the solar mass flows of CMEs as moving cylindrical twisted magnetic flux tubes, the observed instability can be explained in terms of unstable m = -3 MHD mode. We also describe the occurrence of the KH instability in solar jets. The obtained critical jet speeds for the instability onset as well as the linear wave growth rates are in good agreement with the observational data of solar jets.