HELIUM ABUNDANCE, ACCELERATION, AND HEATING AND LARGE-SCALE STRUCTURE OF THE SOLAR WIND

Abstract

This paper summarizes the latest results on the research of solar wind helium ions observed on broad the Prognoz 7 satellite. On the basis of solar wind parameter distributions on the density-velocity plane” we selected five different types of the solar wind streams which may be connected with the well known solar corona structure and phenomena: (1) the heliospheric current sheet, (2) streams from closed coronal magnetic field regions (streamers), (3) streams from open magnetic field regions (coronal holes), (4) disturbed solar wind streams at large angles relative to the axis of non-stationary events in the corona, and (5) disturbed streams near the axis of non-stationary events including the matter of coronal mass ejections. In the streams from streamers the helium abundance decreases with increasing flux in agreement with hypothesis by Gosling et al. (1981) /24/ and in the streams from coronal holes it increases with increasing flux in agreement with model by Geiss et al.(1970) /12/. Preferential α-particle heating and acceleration are generally observed in streams from coronal holes. On the average, equalizations of α-particle and proton velocities and temperatures due to Coulomb collisions are expected to be located at heliocentric distances ~ 7 AU and ~ 20 AU, respectively.