Heidelberg 2006 – scientific programme
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EP: Extraterrestrische Physik
EP 18: Sonne: Energetische Teilchen, Sonnenwind und CMEs
EP 18.1: Fachvortrag
Thursday, March 16, 2006, 10:45–11:00, B
Acceleration and Transport Modeling of Solar Energetic Particle Charge States for the Event of 1998 September 9 — •W. Dröge1, Y. Y. Kartavykh2, B. Klecker3, and G. M. Mason4 — 1Institut für Theoretische Physik und Astrophysik, Universität Würzburg, D-97074 Würzburg — 2Joffe Physical-Technical Institute, St. Petersburg 194021, Russia — 3Max-Planck-Institut für extraterrestrische Physik, D-85741 Garching, Germany — 4Johns Hopkins University, Applied Physics Lab., Laurel, MD 20723
The 1998 September 9 solar particle event was a 3He-rich solar particle event that showed a strong increase of Fe ionization states in the energy range below 1 MeV/nucleon. We have investigated this event by fitting Wind and ACE observations using a model of acceleration and stripping near the Sun, followed by particle transport in the interplanetary medium, taking account of particle focusing, pitch-angle scattering, adiabatic deceleration and convection. The simulation provides a reconstruction of the injection function of the energetic particles released from the Sun and their time, energy and charge dependence. We find that electrons and Fe ions are injected almost impulsively, whereas the injection of protons takes place on a much longer time scale, or even consists of two distinct injection processes. We are able to obtain good overall fits to the observations. This suggests that our model can be used to obtain information about the conditions in the acceleration region such as density, temperature and the time scales of the acceleration process, if sufficiently accurate modeling of the particle transport in the solar wind is possible.