Waves and cold plasma observations near Mars

Abstract

The Phobos-2 spacecraft, initially injected into an elliptical orbit around Mars on 29 January 1989, was subsequently transferred, on 18 February 1989 to a nearly circular orbit, close to that of the Phobos moon, with an areocentric radius of the order of 9600 km. The spacecraft remained in this orbit until the end of the mission, on 27 March 1989. This paper summarizes the plasma and wave observations performed in the night sector of Mars with the Plasma Wave System (PWS), on this circular orbit. Embedded in the magnetic field structure of the Martian tail, cold plasmas with densities in the range 10–65 cm −3 are observed in association with broadband wave activity extending from a few Hz up to several kHz; these plasmas have characteristics analogous to the plasma clouds observed at Venus.