ICS-13 Abstract View

 

Multi-Fluid Simulations Including Kinetic Effects of MMS Reconnection Events
Bhattacharjee, A., amitava@princeton.edu (1)
Hakim, A., ahakim@pppl.gov (2)
Ng, J., jn8@princeton.edu (1)
TenBarge, J., jtenbarg@umd.edu (3)
Since fully kinetic global electromagnetic simulations of magnetospheric plasmas with realistic plasma parameters and system size remain beyond the capability of present petascale or even planned exascale computers over the next 10 years, there has been significant interest in developing extended multi-fluid equations that incorporate kinetic effects through closure relations. We have developed a multi-fluid moment model in the context of collisionless magnetic reconnection. This model evolves full Maxwell equations along with moments of the Vlasov equation for each species in the plasma. Effects like finite particle inertia and pressure tensor that break field lines are self-consistently included in the model without the need to invoke a generalized Ohm's law. At different levels of truncation---5, 10, and 20 moments---we obtain an increasingly detailed description of reconnection dynamics. Whereas the 5-moment model can be shown to be formally equivalent to Hall MHD (in the limit of vanishing electron inertia and infinite speed of light), it neglects heat flux, which is essential in obtaining results that are in reasonable agreement with the results of fully kinetic simulations. For collisionless plasmas, we have tested the efficacy of nonlocal Hammett-Perkins heat flux closure (which includes Landau damping) at the 10 moment level, and the results of our multi-fluid model are shown to be in very good accord with PIC simulations and validated by MMS observations at the dayside magnetopause. We have further extended the scope of these studies by carrying out multi-fluid, 10-moment simulations of fully three-dimensional kinetic ballooning modes of the Earth's magnetotail (in the presence of other kinetic instabilities) as a viable mechanism for substorm onset.
(1) Princeton University
(2) Princeton Plasma Physics Laboratory
(3) University of Maryland, College Park