Importance of Magnetic Reconnecion During the August 24, 2002 Coronal Mass Ejection

N. Lugaz1, I.I. Roussev1, I.V. Sokolov2, C. Jacobs3,1

1Institute for Astronomy - University of Hawaii, USA
2Center for Space Environment Modeling - University of Michigan, USA
3Centrum voor Plasma Astrofysica - KU Leuven, Belgium

The coronal mass ejection (CME) on August 24, 2002, which originated from the western limb, provides an excellent opportunity to study the dynamics and evolution of a fast solar eruption associated with a large solar energetic particle (SEP) event. We employed the Space Weather Modeling Framework (SWMF) to perform a 3-D MHD numerical investigation of the source region and the associated CME. We drive the eruption by stretching the opposite polarity footprints of a small magnetic dipole along the polarity inversion line. Through reconnection at null points and through a quasi-separator, the magnetic flux from the dipole reconnects with the overlaying and neighboring fluxes, resulting in an eruption. Associated with the reconnection process in the corona, the ejection is deflected away from the radial direction towards the Sun-Earth line. Additionally, after the first hour, the flank of the CME propagates into a region of newly open magnetic field connected to the Earth. We believe these two effects are part of the reason why this CME originating from the western limb (W88) was associated with a large SEP events and a interplanetary shock observed at Earth.