Radio fiber bursts and fast magnetoacoustic wave trains

TL;DR

This paper proposes a model where fast sausage magnetoacoustic wave trains explain dm-fiber bursts observed during solar flares, supported by wavelet analysis and MHD simulations, successfully reproducing observed radio spectra.

Contribution

It introduces a semi-empirical and MHD simulation-based model linking magnetoacoustic waves to fiber burst phenomena in solar radio emissions.

Findings

Wavelet tadpoles match fiber burst drift rates

Simulated spectra resemble observed fiber bursts

Magnetoacoustic waves can explain fiber burst dynamics

Abstract

We present a model for dm-fiber bursts that is based on assuming fast sausage magnetoacoustic wave trains that propagate along a dense vertical filament or current sheet. Eight groups of dm-fiber bursts that were observed during solar flares were selected and analyzed by the wavelet analysis method. To model these fiber bursts we built a semi-empirical model. We also did magnetohydrodynamic simulations of a propagation of the magnetoacoustic wave train in a vertical and gravitationally stratified current sheet. In the wavelet spectra of the fiber bursts computed at different radio frequencies we found the wavelet tadpoles, whose head maxima have the same frequency drift as the drift of fiber bursts. It indicates that the drift of these fiber bursts can be explained by the propagating fast sausage magnetoacoustic wave train. Using new semi-empirical and magnetohydrodynamic models with a simple radio emission model we generated the artificial radio spectra of the fiber bursts, which are similar to the observed ones.