Title: Magnetic reconnection driven particle acceleration in macroscale systems: implications for the Parker Solar Probe mission
Speaker: J. F. Drake, University of Maryland
Abstract: A novel MHD/kinetic model is being developed to explore magnetic reconnection and particle energization in macro-scale systems such as the solar corona. The model blends the MHD description with a
macro-particle description. The rationale for this model is based on the recent discovery that energetic particle production during magnetic reconnection is controlled by Fermi reflection and Betatron acceleration and not parallel electric fields. Since the former mechanisms are not dependent on kinetic scales such as the Debye
length and the electron and ion inertial scales, a model that sheds these scales is sufficient for describing particle acceleration in macro-systems. Our MHD/kinetic model includes macroparticles laid out on an MHD grid that are evolved with the MHD fields. Crucially, the feedback of the energetic component on the MHD fluid is included in the dynamics. Thus, energy of the total system, the MHD fluid plus the energetic component, is conserved. The system has no kinetic scales and therefore can be implemented to model energetic particle production in macro-systems with none of the constraints associated with a particle-in-cell (PIC) model. The new model has been benchmarked by studying the propagation of Alfven waves and the growth of firehose modes in a system with anisotropic electron pressure. The talk will emphasize the physics basis for particle acceleration during magnetic reconnection and how this leads to the new model. The prospects for benchmarking this new particle acceleration model with results with solar flare observations and the data from the Parker Solar Probe Mission will be discussed.