Heavy Ions in the Magnetosphere: Results from CLUSTER/CIS

L.M. Kistler, I. Dandouras, C.G. Mouikis, C. Vallat


The CLUSTER spacecraft have now been operating for 3.5 years. The large
geometric factor and fast energy sweeping of the CIS ion composition instrument
on CLUSTER, combined with the multispacecraft capabilities, have allowed
unprecedented measurements of heavy ions in the magnetosphere. In this talk we
will review recent results on heavy ions in the magnetosphere from the
CLUSTER/CIS instrument. We have found that there are time periods throughout the
magnetosphere where heavy ions are a dominant species, effecting the dynamics.
In addition, the heavy ions are always important as a tracer to determine the
sources and transport paths of the ions. We will discuss the impact of heavy
ions on substorm dynamics and reconnection in the magnetotail. Measurements in
the plasmasphere have shown that the density profiles are different for the main
plasma species, and that at CLUSTER altitudes, H+ and He+ are mainly trapped,
while O+ is upwelling. Finally, comparisons between the in situ measurements of
heavy ions from CLUSTER and remote sensing from IMAGE neutral imagers and EUV
measurements have helped to understand the dynamics of the plasmasphere and ring
current.

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Presentation, Fall A.G.U. Meeting, San Francisco, CA, 13-17 December 2004