Solar Physics Talk
Wednesday, Feb. 20, 2008 at 3:30 in Bldg. 26, Rm G10
of Goddard Space Flight Center
Jack Ireland
ADNET, GSFC
Multi-scale Structure of Active Regions
Active regions are complex objects. This study looks at the geometrical distribution of the
longitudinal magnetic field as observed by MDI by decomposing the arrangement of the field on multiple
length-scales. The field gradients between opposite polarity flux elements of multiple length-scale,
is examined for almost 10,000 active regions. These gradients are grouped by Mt. Wilson active region
classification and opposite polarity flux length-scale. It is found that (on average), the Mt. Wilson
classification ranks the (i) maximum, (ii) average and (iii) variance of these field gradients in the
order beta-gamma-delta > beta-gamma > beta > alpha over all length-scales in the active region, and
not just at the smallest scales. This result is independent of the multi-resolution decompositions
used. We also discuss flare activity and their relation to the gradients which appear between
opposite polarity flux regions of different length-scales.
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