YOHKOH and Compton Observations of an LDE Event: Reconnection and the Neupert Effect?
Abstract
We present X-ray images and time profiles of a gradual flare (GOES magnitude M3.2) that occurred on the solar limb at 0430 UT (time of GOES maximum), Feb. 21, 1992. The soft X-ray structure of this event showed a remarkably clear loop development with complicated geometry, including a prominent nearly-vertical bar extending from near the top of the loop(s). During the presence of this bar, the large-area BATSE hard X-ray detector on the Compton Observatory showed extended but highly irregular hard X-ray emission, roughly in the proportion predicted by the ``Neupert Effect'' that associates the integral of the hard X-ray light curve with the instantaneous soft X-ray flux. The peak hard X-ray flux (about 1 ph/(cm(2) sec) above 25 keV) was at 0321 UT, and the emission extended throughout the rise phase of the soft X-ray event. Coronal magnetic reconnection provides a natural interpretation for this morphology, and the time profiles strongly suggest that we can identify the hard X-ray emission with bremsstrahlung from electrons accelerated in the coronal volume of the reconnection region (vertical bar structure).
- Publication:
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American Astronomical Society Meeting Abstracts #180
- Pub Date:
- May 1992
- Bibcode:
- 1992AAS...180.3409H