3D Lattice-Boltzmann Model for Magnetic Reconnection

Abstract

In this paper we develop a 3D Lattice-Boltzmann model that recovers in the continuous limit the two-fluids theory for plasmas, and consecuently includes the generalizated Ohm's law. The model reproduces the magnetic reconnection process just by given the right initial equlibrium conditions in the magnetotail, without any assumption on the resistivity in the diffusive region. In this model, the plasma is handled like two fluids with an interaction term, each one with distribution functions associated to a cubic lattice with 19 velocities (D3Q19). The electromagnetic fields are considered like a third fluid with an external force on a cubic lattice with 13 velocities (D3Q13). The model can simulate either viscous fluids in the incompressible limit or non-viscous compressible fluids, and sucessfully reproduces both the Hartmann flow and the magnetic reconnection in the magnetotail. The reconnection rate obtained with this model is R=0.109, which is in excellent agreement with the observations.