Evolution of Flare-accelerated Electrons Quantified by Spatially Resolved Analysis
arXiv:2004.13155
Abstract
Nonthermal electrons accelerated in solar flares produce electromagnetic emission in two distinct, highly complementary domains - hard X-rays (HXRs) and microwaves (MWs). This paper reports MW imaging spectroscopy observations from the Expanded Owens Valley Solar Array of an M1.2 flare that occurred on 2017 September 9, from which we deduce evolving coronal parameter maps. We analyze these data jointly with the complementary Reuven Ramaty High-Energy Solar Spectroscopic Imager HXR data to reveal the spatially-resolved evolution of the nonthermal electrons in the flaring volume. We find that the high-energy portion of the nonthermal electron distribution, responsible for the MW emission, displays a much more prominent evolution (in the form of strong spectral hardening) than the low-energy portion, responsible for the HXR emission. We show that the revealed trends are consistent with a single electron population evolving according to a simplified trap-plus-precipitation model with sustained injection/acceleration of nonthermal electrons, which produces a double-powerlaw with steadily increasing break energy.
arXiv comment28 pages, 10 figures, accepted in Frontiers in Astronomy and Space Sciences, section Stellar and Solar Physics
References in corpus (8)
- The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
- Global Energetics of Thirty-Eight Large Solar Eruptive Events
- Cold, tenuous solar flare: acceleration without heating
- Magnetography of Solar Flaring Loops with Microwave Imaging Spectropolarimetry
- Broadband microwave burst produced by electron beams
- EOVSA Implementation of a Spectral Kurtosis Correlator for Transient Detection and Classification
- Dynamic Magnetography of Solar Flaring Loops
- Gyrosynchrotron emission generated by nonthermal electrons with energy spectra of a broken power law