Mechanisms of formation of multiple current sheets in the heliospheric plasma sheet

Abstract

<p>When spacecraft cross the heliospheric plasma sheet (HPS) that separates large-scale magnetic sectors of the opposite direction in the solar wind, multiple rapid fluctuations of a sign of the radial magnetic field component are observed very often, indicating the presence of multiple current sheets occurring within the HPS. Possible mechanisms of formation of these structures in the solar wind are proposed. Taking into accout that the streamer belt in the solar corona is believed to be the main source of the slow solar wind in the heliosphere, we suggest that the effect of the multi-layered HPS is determined by the extension of many streamer-belt-borne thin current sheets oriented along the neutral line of the interplanetary magnetic field. Within the framework of a proposed MHD model, self-consistent distributions of the key solar wind characteristics which depend on streamer propreties are investigated. It is shown that both single and multiple streamers that are capable of reaching a remote boundary surface can form the observed multiple current sheets with azimuthal currents alternating in direction inside the HPS. The implications of these results for the interpretation of observations in the solar wind are discussed.</p>