On The Origin of Extreme Events

- Indicates paper has been withdrawn from meeting
- Indicates an Award Winner
Tuesday, 4 February 2014: 5:15 PM
Room C110 (The Georgia World Congress Center )
Scott McIntosh, High Altitude Observatory, UCAR, Bouder, CO; and R. J. Leamon

Approximately once every solar sunspot cycle the Sun can manufacture a superstorms which wreaks havoc with electrical infrastructure on Earth should we be unfortunate enough to be in the direct firing line. Recent work has demonstrated that the sunspot cycle is a direct result of the interaction between the overlapping activity bands of the (fundamental) 22-year magnetic activity cycle. Those activity bands are driven by the rotation of the Sun's deep interior and sunspots are just one signature of its influence on the convective atmosphere above. The number of sunspots present on the disk is directly modulated by the degree of overlap, more overlap leads to fewer spots as there is more sub-surface cancellation of magnetic flux. One (potentially massive) drawback of overlapping activity cycles of opposite sign - and opposite helicity across the equator - is that they are often in very close proximity to one another. Such latitudinal proximity can naturally give rise to conditions where significant amounts of magnetic flux from one band can easily herniate into another and destabilize the surface field with very violent effect. Events of catastrophic size have preferred times in solar cycles and, using a catalog of previous super-storms, we will illustrate that the ideal conditions for another extreme space weather event, much stronger than that of cycle 23, are approaching rapidly, despite the apparently weak appearance of the current solar cycle.