Magnetogram Measures of Total Nonpotentiality for Prediction of Solar Coronal Mass Ejections from Active Regions of Any Degree of Magnetic Complexity

Abstract

For investigating the magnetic causes of coronal mass ejections (CMEs) and for forecasting theCMEproductivity of active regions, in previous work we have gauged the total nonpotentiality of a whole active region by either of two measures, LSSM and LSGM, two measures of the magnetic field along the main neutral line in a vector magnetogram of the active region. This previous work was therefore restricted to nominally bipolar active regions, active regions that have a clearly identifiable main neutral line. In the present paper, we show that our work can be extended to include multipolar active regions of any degree of magnetic complexity by replacing LSSM and LSGM with their generalized counterparts, WLSS and WLSG, which are corresponding integral measures covering all neutral lines in an active re- gion instead of only the main neutral line. In addition, we show that for active regions within 30 heliocentric degrees of disk center,WLSG can be adequately measured from line-of-sight magnetograms instead of vector magnetograms. This approximate measure of active-region total nonpotentiality, LWLSG, with the extensive set of 96 minute cadence full-disk line-of-sight magnetograms from SOHO MDI, can be used to study the evolution of active-region total non- potentiality leading to the production of CMEs.