Authors: Brian T. Welsch (Univ. Wisc. - Green Bay)

Solar flares and coronal mass ejections (CMEs) are manifestations of the sudden release of magnetic energy stored in electric currents that flow in magnetic fields extending from the solar interior into the corona.  However, we lack knowledge about key aspects of these events: What magnetic configurations are necessary (or sufficient) for flares or CMEs to occur?   What evolutionary processes create such configurations?  And what destabilizes them, triggering impulsive energy release?  Consequently, understanding the structure and evolution of flare- and CME-producing magnetic configurations is a key, long-standing problem in solar physics — the “source side” of the heliosphere.  Our lack of understanding represents a major gap in space weather forecasting capabilities — we simply do not know whether or when a given magnetic configuration (such as an active region or a polar crown filament) will produce a flare, or CME, or both. Happily, though, progress is being made, and I will discuss recent developments, in particular the innovative application of Gauss’s separation method to solar magnetic fields and recent, intriguing observations of photospheric magnetic evolution around the time of eruptive flares.