Magnetic helicity and flare activity
Abstract
We studied two active regions appeared in 2001 (NOAA 9415 and 9661), both of which have produced X-class flares. Time evolutions of magnetic flux and magnetic helicity were derived based on vector magnetograph observations. These regions obey the so-called hemispheric rule of magnetic helicity, namely regions in the northern (southern) hemisphere tend to have negative (positive) helicity. The magnetic helicity showed slow evolution but did not show abrupt changes at the time of flares. Flare activity was correlated with changes in the distributions of magnetic helicity that were driven by horizontal flows.
- Publication:
-
34th COSPAR Scientific Assembly
- Pub Date:
- 2002
- Bibcode:
- 2002cosp...34E2093S