1. Distinguishing Eruptive from Non-Eruptive Solar Active Regions Manolis K. Georgoulis JHU/APL 11100 Johns Hopkins Rd., Laurel, MD 20723 Durham, NH, 06/27/06 Partially supported by LWS TR&T

2. Sufficient statistics needed Eruptive active regions:  |H m | > 10 43 Mx 2  (E free /E tot ) > 0.10 Non-eruptive active regions:  |H m | < 10 43 Mx 2  (E free /E tot ) < 0.05 |H m | (x 10 42 Mx 2 ) Relative magnetic free energy Large helicity – little free energy Large free energy – little helicity (suggested by models) Durham, 06/27/06 12/13

3. Force-free model of energy/helicity budget calculation A surface-integral representation of all energy – helicity terms in the FF approximation (Georgoulis & LaBonte 2006, ApJ, submitted) Constant alpha OPERATIONAL Variable alpha TO BE IMPLEMENTED Durham, 06/27/06 10/13 where extending the analysis of Berger (1985)