Solar Wind Tail and the Anisotropic Production of Fast Hydrogen Atoms

Abstract

THE flow of supersonic solar wind is supposed to be reduced to subsonic velocities and randomized at a so-called shock front somewhere between 5 and 50 AU from the Sun. The position of the shock front is roughly determined by the condition that the energy density of the solar wind plasma should be comparable with that of the interstellar magnetic field. Patterson et al.¹ have found that half the flux of the solar wind protons is returned to the heliosphere at the shock front in the form of fast neutral hydrogen atoms produced in charge exchange processes supposed to take place in a thin shell around the shock front. This return flux is a consequence of the thin shell model and the assumption that all the solar wind protons which pass the shock front undergo charge exchange with interstellar hydrogen.