Association of Low-Charge-State Heavy Ions up to 200 Re upstream of the Earth’s bow shock with geomagnetic disturbances

[1] We present the first study of Low-Charge-State Heavy Ion (LCSHI) events covering a region from Earth’s bow shock to the L1 point, obtained with the Suprathermal Ion Composition Spectrometer onboard Wind. STICS is capable of distinguishing charge states of suprathermal ions. In 1995–2000 we found a large number of particle events revealing species of magnetospheric origin. LCSHI events tend to occur in series and in connection with geomagnetic activity. The occurrence rate is found to increase towards solar maximum. The spatial region covered by this particle population ranges from the bow shock to beyond distances of 130 Re, where one of the strongest events occurred. Based on the characterization of LCSHI events we discuss mechanisms for their formation. We conclude that the most probable sources of these ion events are substorms in association with Alfvén waves in highspeed solar wind streams and the magnetic storm recovery ring current.