Magnetic Causes of Solar Coronal Mass Ejections: Dominance of the Free Magnetic Energy over Either the Magnetic Twist or Size Alone
Abstract
We report further results from our ongoing assessment of magnetogram-based measures of active-region nonpotentiality and size as predictors of coronal mass ejections (CMEs). We have devised improved generalized measures of active-region nonpotentiality that apply to active regions of any degree of magnetic complexity, rather than being limited to bipolar active regions as our initial measures were. From a set of 50 active-regions, we have found that measures of total nonpotentiality have a 75-80% success rate in predicting whether an active region will produce a CME within 2 days after the magnetogram. This makes measures of total nonpotentiality a better predictor than either active-region size, or active-region twist (size-normalized nonpotentiality), which have 65% success rates. We have also found that we can measure from a line-of-sight magnetogram an active region's total nonpotentiality and the size, which allows use of to use MDI to evaluate these quantities for 4-5 consecutive days for each active region, and to investigate if there is some combination of size and total nonpotentiality that have a stronger predictive power than does total nonpotentiality.This work was funded by NASA through its LWS TR&T Program and its Solar and Heliospheric Physics SR&T Program, and by NSF through its Solar Terrestrial Research and SHINE Programs.
- Publication:
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AAS/Solar Physics Division Meeting #37
- Pub Date:
- June 2006
- Bibcode:
- 2006SPD....37.2004F