Oxygen Injections Into the Ring Current: Simultaneous Inner Magnetosphere and Tail Observations J.-M. Jahn (Southwest Research Institute, San Antonio, TX 78228), H.A. Elliott, W.K. Peterson, K.J. Trattner, P.C:Son Brandt, D.G. Mitchell, R.H.W. Friedel We are investigating the circulation of ionospheric O+ in the magnetosphere by using a combination of POLAR and Cluster in situ oxygen plasma and IMAGE neutral oxygen remote sensing measurements starting in the Fall months of 2001. IMAGE energetic neutral atom observations of the inner magnetosphere/ ring current show that significant - yet highly variable - quantities of oxygen are mostly observed during geomagnetic storms, and that they are delivered in bursts by substorm activity. Isolated non-storm substorms, on the other hand, typically show little to no contribution of oxygen to the inner magnetosphere. With Polar and Cluster located in the plasma sheet for extended amounts of time we can locally determine the oxygen content and tail dynamics associated with those injections, adding to our understanding of M-I coupling. Likewise, these observations can be used as baseline for correlations with oxygen meas-urements outside the magnetosphere. ________________ Presentation at the Yosemite Conference of Inner Magnetospheric Interactions, 3 - 6 February 2004, Yosemite, California, USA