1. Threshold of measures of active regions and solar activities Yang Liu – Stanford University yliu@solar.stanford.edu

2. Results for the entire solar cycle 23 / SoHO MDI LaBonte et al. (2006) X-flaring ARs |(dH m / dt)| > 6 x 10 36 Mx 2 s -1 X-flaring ARs appear to to have a lower threshold in their peak helicity rates Durham, 06/27/06 08/13 This slit is from M. Georgoulis’ presentation made in 2006 SPD.

3. 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 Durham, 06/27/06 12/13 This slit is from M. Georgoulis’ presentation made in 2006 SPD.

4. Flare productivity vs magnetic gradient Flare productivity vs length of neutral line Flare productivity vs number of singular points From Cui et al (2006) Flare productivity index is defined as: p(x)=s(x)/t(x), where s is the number of active regions with a measure greater than x, while t is total number.