Solar wind interaction with the terrestrial magnetopause

Sammanfattning: Magnetic reconnection plays an important role in the transfer of mass, energy and momentum from the solar wind to the terrestrial magnetosphere. The earliest contributions to the theory of magnetic reconnection dates from the beginning of the 1930's. However, it took until the end of the 1950's when Sweet and Parker made their first reconnection model, for the concept to reach a somewhat solid ground. During the years since then magnetic reconnection has walked through the phase of reaching mythical proportions where some researchers believed in it, and some not, to the acceptance it has today where the main issue not is whether the process happens or not, but rather the main physical properties and the implications of it. During the last fifteen years much of the research due to the rapid increase in computer capacity, treats numerical simulations of magnetic reconnection. Theoretical analysis keeps though its position as a cornerstone for the understanding of the process. But also for the base of new implemented models. Much of the theoretical work accomplished to this day has its focus on magnetic reconnection itself; applications for different conditions, and the onset of the process - something which still is under much discussion among researchers. This work focuses on the implications of magnetic reconnection in combination with the outer magnetosheath flow. The analysis treats a two-dimensional and three-dimensional case. For the 3D case, the magnetosheath plasma flow is considered to be incompressible, while we for the 2D case also treat a compressible magnetosheath plasma. Magnetic reconnection is assumed to occur in a region stretching from the sub-solar point to the north, at an arbitrary point for the 2D case, and along a line parallel to the y-axis for the 3D case. The analysis is based on the MHD equations including dissipative effects such as viscosity and resistivity, where the equations are solved approximately by the use of an ordinary perturbation expansion for large Reynolds and Lundqvist numbers. The objective of the 2D study treating an incompressible plasma flow, is to get a description of the current transition layer in combination with the outer magnetosheath and boundary layer flow. The solutions are asymptotically matched with an existing model for the magnetosheath magnetic field. For the 2D compressible case and 3D analysis, the objective is to study the development of the magnetic field and total velocity during the transition from the magnetosheath to the magnetosphere.