Impact of the Interplanetary Magnetic Field to Impingement of a Solar Wind Rotational Discontinuity on the Earth’s Bow Shock

Abstract

The impact of the plane front of an interplanetary rotational discontinuity, which has a circular polarization and propagates in the solar wind along the Sun-Earth radius, on the Earth's bow shock and the magnetosheath is investigated in the three-dimensional formulation. The most characteristic values of the solar wind parameters and the interplanetary magnetic field strength in the Earth's orbit are considered. The global three-dimensional pattern of the flow is constructed as a mosaic of exact solutions of the Riemann problem of breakdown of the MHD discontinuity behind the interacting waves. The exact solutions are found numerically in computer using an original Riemann solver for the non-plane-polarized three-dimensional magnetohydrodynamic Riemann problem. The pattern developed is a function of the latitude and longitude of points on the surface of the bow shock. It is found that all the waves and discontinuities appearing in the interaction significantly depend on the angle of rotation of the magnetic field and their type can transform in the process of propagation. The waves are found using relations on strong MHD discontinuities for fast and slow shocks and rotational discontinuities and systems of ordinary differential equations for rarefaction waves.