Plasma Motions and Heating by Magnetic Reconnection in a 2007 May 19 Flare
Abstract
Based on scanning spectroscopic observations with the Hinode EUV imaging spectrometer, we have found a loop-top hot source, a fast jet nearby, and an inflow structure flowing to the hot source that appeared in the impulsive phase of a long-duration flare at the disk center on 2007 May 19. The hot source observed in Fe XXIII and Fe XXIV emission lines has the electron temperature of 12 MK and density of 1 × 1010 cm-3. It shows excess line broadening, which exceeds the thermal Doppler width by ~100 km s-1, with a weak redshift of ~30 km s-1. We have also observed a blueshifted faint jet whose Doppler velocity exceeds 200 km s-1 with an electron temperature of 9 MK. Coronal plasmas with electron temperature of 1.2 MK and density of 2.5 × 109 cm-3 that flow into the loop-top region with a Doppler velocity of 20 km s-1 have been identified in the Fe XII observation. They disappeared near the hot source, possibly by being heated to the hotter faint jet temperature. From the geometrical relationships of these phenomena, we conclude that they provide evidence for magnetic reconnection that occurs near the loop-top region. The estimated reconnection rate is 0.05-0.1, which supports the Petschek-type magnetic reconnection. Further supporting evidence for the presence of the slow-mode and fast-mode MHD shocks in the reconnection geometry is given based on the observed quantities.
- Publication:
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The Astrophysical Journal
- Pub Date:
- November 2011
- DOI:
- 10.1088/0004-637X/741/2/107
- Bibcode:
- 2011ApJ...741..107H
- Keywords:
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- Sun: corona;
- Sun: flares;
- Sun: UV radiation