Searching for a termination shock in a well-observed limb flare
Abstract
We examine a well-observed flare that occurred on the limb of the Sun on March 7, 2015 in order to find possible signatures of a termination shock due to outflows from reconnecting magnetic fields. Images of this flare from Hinode/XRT and the SDO/AIA 131 bandpass show a cusp-shaped morphology. The IRIS slit was positioned in the region of the current sheet, above the flare loops. Fe XXI is detected in the IRIS spectra with an average Doppler velocity of about 20 km/s. The non-thermal widths in IRIS decrease steadily from 23:00 UT on the 7th until 00:20 UT the next day, but there is no strong evidence that the slit crossed a termination shock. Data from Nobeyama Radioheliograph (NoRH) is primarily due to thermal free-free emission based on the examination of NoRH images at 17 GHz and 34 GHz, and RHESSI data shows a thermal looptop source at 6-10 keV. The lack of non-thermal emission in this data implies that there is no shock region that accelerates particles. However, neither of these instruments were observing during the impulsive phase of the flare, which peaked at about 22:25 UT. We also investigate the temperature structure of the flare using XRT and AIA data, and do not find any evidence for a termination shock.
- Publication:
-
Solar Heliospheric and INterplanetary Environment (SHINE 2017)
- Pub Date:
- July 2017
- Bibcode:
- 2017shin.confE..66R