The observation of 2017-09-09 M1.2 flare by the Expanded Owens Valley Solar Array and The Reuven Ramaty High Energy Solar Spectroscopic Imager
Abstract
We present the observation of the near-limb M1.2 flare on 2017 September 9 successfully done by the newly commissioned Expanded Owens Valley Solar Array (EOVSA) and the The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). During its impulsive phase, this flare exhibited an interesting delayed response in microwave (MW) high frequency emission (peaking at 22:50 UT) compared to the several hard X-ray (HXR) peaks starting from 22:26 UT. The initial analysis shows at least one footpoint source that is co-spatial in HXR 25-50 keV and MW optically-thin frequency at 22:50 UT, indicating the existence of nonthermal particle acceleration and precipitation to the chromosphere. The spatially-integrated spectrum at this time reveals a rather low peak frequency 4 GHz, and the MW source is observed to be located at progressively higher altitude and occupying broader area. We interpret this result in the light of the large, high-altitude nonthermal particle population that have been discussed in recent studies.
- Publication:
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Solar Heliospheric and INterplanetary Environment (SHINE 2018)
- Pub Date:
- July 2018
- Bibcode:
- 2018shin.confE.244K