AR11476: Magnetic Thumbprint

AR11476 - like all sunspots was a wholly magnetic structure. This overlay places the white-light and H-alpha image over the Mt Wilson magnetogram (c) Regents of University of California, at close-to the same time and orientation. The colour background hi-lights the two different magnetic 'signs' of the field structures that create the sunspot. The yellow region is 150 gauss preceding polarity, and green is 150G following polarity. We can see how much larger is the magnetic "footprint" compared to the sunspot itself - and the spot was big, it had an area ~1000units. Note that fields inside the spot umbrae are 15 times stronger than background (2400G cf to 150G)

Active Region Filament (ARF): note that the filament (heavy black line) occurs at the narrow boundary between opposite polarities - termed the Inversion Line: flares will occur along this line.
The Inversion Line is a strong feature that might well reappear around June 2nd. Will any sunspots have survived? Why don't opposite fields simply reconnect across the filament boundary (or channel)? That is a good question. It's known that field lines run in opposite directions parallel to the channel - and somehow that acts as an insulator - at least until a flare occurs.