Evolution of the radio signatures of energetic electrons from the flare acceleration site to the high corona

Sophie Musset - University of Glasgow; Eduard Kontar - University of Glasgow, United Kingdom; Nicole Vilmer - LESIA, Paris Observatory, France; Lindsay Glesener - University of Minnesota, United States; Abdallah Hamini - LESIA, Paris Observatory, France

Session: The solar sources of space weather

Abstract

Solar energetic electrons are an important component of space weather which can be accelerated during solar flares. While such electrons are detected in-situ in the heliosphere, the study of the acceleration and injection processes in the solar corona rely on their signatures in X-ray and radio observations. When both signatures are observed, their combination lead to a detailed understanding of the acceleration, injection and propagation of energetic electron beams in the corona. We present the case of such events in the gradual phase of the GOES M4 flare on September 9 2017 at 11:04 UT, for which X-ray signatures of non-thermal electrons correlate in time with type III radio bursts extending from the acceleration site to the high corona (600 to 30 MHz). This event was observed with the LOFAR radio-telescope, providing images of the radio sources in the high corona (30-50 MHz) at unprecedented frequency resolution. Using this set coverage, we study the evolution of the radio source sizes with their radial distance from the Sun and provide evidence that radio-wave scattering contribute largely to the characteristic of the sources of radio coherent emission tracing the propagation of the energetic electron beams in the corona and the heliosphere.