An imaging study of a complex solar coronal radio eruption

TL;DR

This study uses simultaneous EUV and radio imaging to analyze a complex solar radio eruption, revealing the association of type II bursts with CME-driven shocks and type III bursts with reconnection within ejecta, advancing understanding of solar energetic particles.

Contribution

It provides the first detailed imaging analysis linking radio burst sources with specific coronal structures during a complex eruption, enhancing understanding of particle acceleration mechanisms.

Findings

Type II burst linked to CME-driven EUV shock structure.

Electron acceleration estimated at ~0.3c at shock flank.

Reversely-drifting type III bursts associated with reconnection within ejecta.

Abstract

Solar coronal radio bursts are enhanced radio emission excited by energetic electrons accelerated during solar eruptions, studies on which are important for investigating the origin and physical mechanism of energetic particles and further diagnosing coronal parameters. Earlier studies suffered from a lack of simultaneous high-quality imaging data of the radio burst and the eruptive structure in the inner corona. Here we present a study on a complex solar radio eruption consisting of a type II and three reversely-drifting type III bursts, using simultaneous EUV and radio imaging data. It is found that the type II burst is closely associated with a propagating and evolving CME-driven EUV shock structure, originated initially at the northern shock flank and later transferred to the top part of the shock. This source transfer is co-incident with the presence of shock decay and enhancing signatures observed at the corresponding side of the EUV front. The electron energy accelerated by the shock at the flank is estimated to be $\sim$ 0.3 c by examining the imaging data of the fast-drifting herringbone structure of the type II burst. The reversely-drifting type III sources are found to be within the ejecta and correlated with a likely reconnection event therein. Implications on further observational studies and relevant space-weather forecasting techniques are discussed.