Multiple Regions of Shock-accelerated Particles during a Solar Coronal Mass Ejection

TL;DR

This study uses multi-instrument imaging to reveal multiple regions of shock-accelerated particles during a fast solar CME, supporting theories of non-uniform shock fronts in the solar corona.

Contribution

It provides the first detailed imaging evidence of multiple shock regions and electron beams along an expanding CME in the solar corona.

Findings

Multiple shock regions identified during CME expansion

Electron beams observed at various locations along the CME

Supports non-uniform, rippled shock front theories

Abstract

The Sun is an active star that can launch large eruptions of magnetised plasma into the heliosphere, called coronal mass ejections (CMEs). These ejections can drive shocks that accelerate particles to high energies, often resulting in radio emission at low frequencies (<200 MHz). To date, the relationship between the expansion of CMEs, shocks and particle acceleration is not well understood, partly due to the lack of radio imaging at low frequencies during the onset of shock-producing CMEs. Here, we report multi-instrument radio, white-light and ultraviolet imaging of the second largest flare in Solar Cycle 24 (2008-present) and its associated fast CME (3038+/-288 km/s). We identify the location of a multitude of radio shock signatures, called herringbones, and find evidence for shock accelerated electron beams at multiple locations along the expanding CME. These observations support theories of non-uniform, rippled shock fronts driven by an expanding CME in the solar corona.