A Goodbye Gift From AR1476: The First Ground Level Enhancement Event of Solar Cycle 24
Abstract
We provide an overview of the M-class flare and O-type* coronal mass ejection (CME) that occurred on May 17, 2012 as AR1476 was passing behind the solar disk. This event is special because the long duration flare and well-timed CME produced a solar energetic particle (SEP) event that resulted in the first Ground Level Enhancement (GLE) of Solar Cycle 24. At the Goddard Space Weather Center, we performed real time analysis of the action, and gave a preliminary predicted ICME arrival time at NASA"s STEREO-A spacecraft that was within one hour of the actual arrival. The CME possibly facilitated the GLE in two ways: 1) the CME-driven shock could have contributed to the acceleration of very high-energy protons required for a GLE, and 2) the CME could have disturbed the coronal magnetic field, widening the longitudinal extent of the SEP event. This event underscores the need for global modeling of CME-driven shocks in the low corona. We discuss CME simulations performed with the Space Weather Modeling Framework"s wave-driven solar wind model, and emphasize the global structure of the eruption as a key to understanding particle acceleration. Comparisons are made between this event and the March 7, 2012 X-class flares and R-type* CME.*O-type (Occasional), R-type (Rare) on the CME SCORE Scale (see http://youtu.be/hN5bChbdky8 for more details). For an overview of the event, see the Special Space Weather Report: http://youtu.be/8jutX8JgXIw
- Publication:
-
Solar Heliospheric and INterplanetary Environment (SHINE 2012)
- Pub Date:
- June 2012
- Bibcode:
- 2012shin.confE..29E