A Numerical Model of the CME Event on 1998 May 2

Authors: I.I. Roussev, I.V. Sokolov, T.I. Gombosi; T.G. Forbes, M.A. Lee
Affiliation: University of Michigan; University of New Hampshire

We present modeling results on the initiation and evolution of the coronal mass ejection which occurred on 1998 May 2 in NOAA AR8210. This is done within the framework of a global model of the solar magnetic field as it was observed by the Wilcox Solar Observatory on 1998 May 2. On this day, a CME associated with an X1.1/3B flare occurred in NOAA AR8210 at 13:42 UT, which was associated with an SEP event observed by the NOAA GOES-9 satellite. A ground-level event was also observed by the CLIMAX neutron monitor.
For this event, diffusive-shock-acceleration theory predicts a distribution of solar energetic protons with a cut-off energy of about 10 GeV. Thus, there appears to be no need to introduce an additional acceleration mechanism to account for solar energetic protons with energies below 10 GeV. We conclude that a CME-driven shock can develop close to the Sun sufficiently strong to account for energetic particles at such high energies.