Ultraviolet Emissions and Magnetic Field Changes during Solar Flares
Abstract
We compare ultraviolet emissions from the chromosphere, obtained from Transition Region and Coronal Explorer (TRACE) images, and longitudinal magnetic field changes in the photosphere, obtained from Global Oscillation Network Group (GONG) magnetograms, during five X-class solar flares. An abrupt, significant, and persistent change in the magnetic field occurred across more than ten pixels in the GONG magnetograms during each flare. In all cases, ultraviolet emissions occur along the same line of sight as the field changes. The ultraviolet emissions lag the GOES x-ray start times for the flares and lead the changes in the magnetic field with the longest time delay being no more than 13 minutes. The ultraviolet emissions decay well after the field changes are complete. The observations are consistent with the picture in which an Alfven wave from the field reconnection site in the corona propagates outward in all directions, including downwards through the chromosphere and into the photosphere.
- Publication:
-
American Astronomical Society Meeting Abstracts #219
- Pub Date:
- January 2012
- Bibcode:
- 2012AAS...21914402J