Simulating the Interaction of Magnetic Flux Ropes using Magnetohydrodynamics with Adaptively Embedded Particle-In-Cell (MHD-AEPIC) Model

In general, collisionless magnetic reconnection simulations require kinetic approaches that are computationally expensive in comparison with fluid codes. In this presentation, we use the magnetohydrodynamics with adaptively embedded particle-in-cell (MHD-AEPIC) model to simulate the problem of flux-rope merging. The MHD-AEPIC model applies kinetic treatments only in regions where kinetic physics is significant by embedding adaptive particle-in-cell regions into a global MHD simulation domain. We compare the simulation results of reconnection rates, magnetic island O-point separations, and the structures of the out-of-plane current densities, ion pressure tensor elements, and ion agyrotropy using the MHD-AEPIC model, the MHD-EPIC model with statically embedded PIC regions, and an explicit PIC code. The comparison yields excellent agreement among the three simulation approaches, validating the physical accuracy of the MHD-AEPIC model. In addition to modeling the global magnetospheres efficiently and accurately, the MHD-AEPIC model can also be applied to simulate FLARE and NSTX-U at Princeton Plasma Physics Laboratory, MAST at the UK as well as TREX at Wisconsin Plasma Physics Laboratory.