Global structure of the heliosphere: 3D kinetic-MHD model and the interpretation of spacecraft data

Abstract

This paper is a brief overview of research into the interaction between the solar wind and local interstellar medium. This interaction determines the global structure of the heliosphere (the region occupied by the solar wind) and has a complex multicomponent character. We describe the three-dimensional kinetic-magnetohydrodynamic model of the interaction, which includes plasma and neutral components of the interstellar medium and solar wind, the heliospheric and interstellar magnetic fields, and the latitudinal and temporal variations of solar wind parameters. In describing the results, magnetic-field-related effects are given special attention, in particular, the magnetic-field-driven plasma depletion in the vicinity of the heliopause. The model explains a sufficiently large body of data from Voyager-1 and Voyager-2, the Interstellar Boundary Explorer (IBEX), the Solar and Heliospheric Observatory (SOHO), the Hubble Space Telescope (HST), and other spacecraft. Based on the experimental data and using the model, the parameters of the interstellar medium and of the interstellar magnetic field are determined. It is shown, however, that a single model using a single set of boundary conditions cannot self-consistently explain all the data available. The Voyager-1 data on the scattered solar Lyman-alpha radiation is taken as an example to illustrate the difficulties that arise.