MHD Modeling of Magnetic Reconnection Shock Structure at the Dayside Magnetopause

Abstract: Magnetic reconnection is a plasma phenomenon where the frozen-in magnetic field lines of a magnetic field breaks down locally and reconnects to other field lines, thus causing a rearrangement of the magnetic topology. This process allows for a release of energy, where magnetic energy stored in the current sheet is transformed into kinetic and thermal energy, forming high-speed plasma outflows from the point of reconnection. This thesis aims to investigate the structure and relative magnitude of different physical quantities in the produced plasma outflow regions, and identify arising magnetohydrodynamic (MHD) discontinuities. The setting investigated in this thesis is the dayside of the terrestrial magnetopause where reconnection is assumed to occur when the interplanetary magnetic field and the terrestrial magnetic field interacts.

A two-dimensional, steady-state, compressible, non-viscous and non-resistive model is created in the COMSOL Multiphysics modeling environment, a software capable of handling couple physical effects, and solving the involved partial differential equations (PDEs) simultaneously, PDEs which are derived from the MHD description. The model is investigated specifically regarding the effect of a non-zero tangential component of the magnetosheath plasma flow, colliding with the magnetopause. The results are presented in form of surface-plots and one-dimensional plots, for both the south- and northward plasma outflows emanating from the point of reconnection, displaying the relative quantities of the different variables involved. Slow shocks and a contact discontinuity is found by analyzing the resulting one-dimensional plots.