“Reduced” multidimensional Vlasov simulations, with applications to electrostatic structures in space plasmas

Abstract

A class of two-dimensional open-boundary kinetic plasma simulations characterized as reduced Vlasov simulations have been developed and applied to the study of double layers and electron holes in Earth’s auroral downward current region. In these simulations, full Vlasov phase-space dynamics is followed only in the direction of the magnetic field or imposed current, with a limited representation of phase space employed in the perpendicular spatial dimension. These reduced methods include a dissipative moment closure for unmagnetized species and limitation of perpendicular velocity space to a ring of modes at a fixed v⊥ for weakly magnetized species. Simulations with weakly magnetized ions exhibit ion-Bernstein waves in association with electron holes and simulations with weakly magnetized or unmagnetized electrons result in electron holes elongated perpendicular to B. These results are in qualitative agreement with satellite observations and previous particle simulations.