Magnetospheric Ions Upstream of the Bow Shock

Six years of observations in the upstream region of the Earth's bow shock have revealed the circumstances under which suprathermal magnetospheric origin ions escape sunward. The long-term trends, spectral and charge state composition of these events will be discussed. Two classes of magnetospheric outflow have been identified, both occuring mainly under southward IMF conditions. First, in high speed solar wind streams, series of short bursts of magnetospheric ions can typically be observed on the time scale of Alfvénic fluctuations. Second, magnetic clouds of ICMEs are linked to highly structured flux tubes of magnetospheric ions. Analysis of one of these events has revealed non-gyrotropic ion outflow from the magnetosphere along a reconnected field line during the main reovery phase of the Earth's ring current.