Particle Acceleration by a Solar Flare Termination Shock

TL;DR

This paper provides observational evidence of a solar flare termination shock and demonstrates its role in accelerating energetic electrons, supported by high-resolution radio imaging and simulations.

Contribution

It offers the first detailed observations of a solar flare termination shock and confirms its significance in particle acceleration through combined imaging and modeling.

Findings

Disruption of the shock correlates with electron population reduction.

Observed shock properties match simulation results.

Supports the role of termination shocks in solar flare particle acceleration.

Abstract

Solar flares - the most powerful explosions in the solar system - are also efficient particle accelerators, capable of energizing a large number of charged particles to relativistic speeds. A termination shock is often invoked in the standard model of solar flares as a possible driver for particle acceleration, yet its existence and role have remained controversial. We present observations of a solar flare termination shock and trace its morphology and dynamics using high-cadence radio imaging spectroscopy. We show that a disruption of the shock coincides with an abrupt reduction of the energetic electron population. The observed properties of the shock are well-reproduced by simulations. These results strongly suggest that a termination shock is responsible, at least in part, for accelerating energetic electrons in solar flares.