High mode magnetohydrodynamic waves propagation in a twisted rotating jet emerging from a filament eruption

TL;DR

This study investigates the conditions under which high mode MHD waves on a twisted, rotating solar jet become Kelvin-Helmholtz unstable, revealing specific wavelengths, instability times, and the influence of magnetic twist on mode numbers.

Contribution

It models a twisted rotating magnetic flux tube to analyze high mode MHD wave propagation and instability criteria, providing new insights into wave behavior in solar jets.

Findings

Unstable MHD waves with wavelengths of 12-15 Mm identified.

Instability development times range from 1.5 to 2.6 minutes.

Azimuthal mode number depends on magnetic twist, with m=16 for slight twist and m=18 for moderate twist.

Abstract

We study the conditions under which high mode magnetohydrodynamic (MHD) waves propagating on a rotating jet emerging from the filament eruption on 2013 April 10--11 can became unstable against the Kelvin--Helmholtz instability (KHI). The evolution of jet indicates the blob like structure at its boundary which could be one of the observable features of the KHI development. We model the jet as a twisted rotating axially moving magnetic flux tube and explore the propagation characteristics of the running MHD modes on the basis of dispersion relations derived in the framework of the ideal magnetohydrodynamics. It is established that unstable MHD waves with wavelengths in the range of $12$--$15$~Mm and instability developing times from $1.5$ to $2.6$~min can be detected at the excitation of high mode MHD waves. The magnitude of the azimuthal mode number $m$ crucially depends upon the twist of the internal magnetic field. It is found that at slightly twisted magnetic flux tube the appropriate azimuthal mode number is $m = 16$ while in the case of a moderately twisted flux tube it is equal to $18$.