Structure of the Jovian magnetospheric boundary region.

Abstract

A structure of the Jovian magnetospheric boundary region near the equatorial plane which is produced by the interaction between the solar wind plasma and the internal planetary wind plasma in the magnetodisc, has been studied. A possibility of the existence of the internal shock, as a innermost boundary between the planetary wind and the region of the intrinsic magnetic field, has been investigated theoretically using two dimensional Rankine-Hugoniot relation in MHD regime. The results of present numerical calculation for the internal shock indicate the asymmetrical characteristics; that is, the internal shock is strong in the dawn side of the Jovian magnetodisc, while the shock formed in the dusk side is weak and disappears at the intermediate position reflecting the azimuthally flowing nature of the Jovian disc wind.A unique model of the Jovian low latitude magnetospheric boundary structure which consists of the double shock (bow shock and internal shock) and the double magnetopause (magnetopause and internal magnetopause), has been proposed. The data obtained by the in-situ observations suggest the existence of the theoretically proposed boundary structure. This coincidence suggests a indirect confirmation of the existence of the Jovian disc wind which is proposed on the theoretical base.