Imaging-Spectroscopy of CME-Associated Solar Radio Emission using OVRO-LWA
Abstract
Radio emission from the solar corona provides a unique perspective on the physical properties of energetic phenomena, such as solar flares and coronal mass ejections (CMEs). We use the new state-of-the-art Owens Valley Radio Observatory - Long Wavelength Array (OVRO-LWA) for the purpose. We examine a complex event consisting multiple radio sources/bursts associated with a fast CME and a M2.1 GOES SXR flare from 2015 Sep 20, as well as quiet Sun images before and after the bursts. Images of 9-s cadence are used to analyze the event over a 90-minute period, out to a distance of ~3 Rsun, over the frequency range of 40-70 MHz available at that time.
We present our results from the investigation of the radio sources, focusing particularly on one burst source that exhibits outward motion. In order to understand better the evolution of the burst, we image the event at hundreds of frequencies and use the source centroids to obtain the velocity for the outward motion. A coalignment with LASCO(C2) allows a spatial and temporal comparison with observations of the CME in white light indicating an association of the outward motion with the core of the CME. We perform graduating-cylindrical-shell reconstruction of the CME to constrain the density in the volume to verify that the emission from the moving source is not consistent with plasma emission, and therefore is likely due to gyrosynchrotron emission. This then allows the use gyrosynchrotron spectral fitting techniques to estimate the evolving physical conditions. The results suggest that both accelerated electron density and magnetic field strength decline as the source expands outward, while the powerlaw index of the electrons hardens.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSH21B..03C
- Keywords:
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- 7514 Energetic particles;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7519 Flares;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7845 Particle acceleration;
- SPACE PLASMA PHYSICS;
- 7859 Transport processes;
- SPACE PLASMA PHYSICS