Pre-eruption magnetic configurations in the active-region solar photosphere

Abstract

Most solar eruptions occur above strong photospheric magnetic polarity inversion lines (PILs). What overlays a PIL is unknown, however, and this has led to a debate over the existence of sheared magnetic arcades vs. helical magnetic flux ropes. We argue that this debate may be of little meaning: numerous small-scale magnetic reconnections, constantly triggered in the PIL area, can lead to effective transformation of mutual to self magnetic helicity (i.e. twist and writhe) that, ultimately, may force the magnetic structure above PILs to erupt to be relieved from its excess helicity. This is preliminary report of work currently in progress. © International Astronomical Union 2011.