Study of flare energy release using events with numerous type III-like bursts in microwaves

TL;DR

This study investigates the energy release in solar flares by analyzing fast-drifting microwave bursts with high-resolution radio imaging, revealing source locations and electron dynamics in flare loops.

Contribution

It presents a novel analysis of type III-like bursts during a solar flare using multiwavelength radio data and high-resolution imaging to determine source positions and electron velocities.

Findings

Sources located near the top of the flare loop

High pitch-anisotropy of emitting electrons

Drift rates ranged from -7 to 13 GHz/s

Abstract

The analysis of narrowband drifting of type III-like structures in radio bursts dynamic spectra allows to obtain unique information about primary energy release mechanisms in solar flares. The SSRT spatially resolved images and a high spectral and temporal resolution allow direct determination not only the positions of its sources but also the exciter velocities along the flare loop. Practically, such measurements are possible during some special time intervals when the SSRT (about 5.7 GHz) is observing the flare region in two high-order fringes; thus, two 1D scans are recorded simultaneously at two frequency bands. The analysis of type III-like bursts recorded during the flare 14 Apr 2002 is presented. Using-muliwavelength radio observations recorded by SSRT, SBRS, NoRP, RSTN we study an event with series of several tens of drifting microwave pulses with drift rates in the range from -7 to 13 GHz/s. The sources of the fast-drifting bursts were located near the top of the flare loop in a volume of a few Mm in size. The slow drift of the exciters along the flare loop suggests a high pitch-anisotropy of the emitting electrons.