Loop structures in the July 19, 1999 solar flare
Abstract
Comparing the SOHO/EIT 195 Å and Hα images (Hvar and Modra Observatories) with the magnetic field extrapolations of SOHO/MDI magnetograms the loop structures of the July 19, 1999 flare were analyzed. The presence of the current-carrying flux rope was identified by its deviation from the current-free magnetic field extrapolation and "umbrella hand" shape of the Hα ribbons. After the flare start in the neighboring "cone" arcade this current-carrying flux rope interacts (reconnects) with this arcade, forming thus flare loops spanning over both these magnetic structures. During these processes several cross-loop structures appeared. One of them indicates the flare loop interaction. At this space the extended helical structure, possibly a remnant of some current-carrying flux rope, was found. The pitch angle of this helical thread θ = 61° was determined. Assuming then the magnetic field as 10-4 - 10-3T, the total electric current in the helical structure was estimated as J = 4.8×(109 - 1010)A.
- Publication:
-
Solspa 2001, Proceedings of the Second Solar Cycle and Space Weather Euroconference
- Pub Date:
- March 2002
- Bibcode:
- 2002ESASP.477..143K
- Keywords:
-
- Solar Flares;
- Magnetic Field