HR: 12:05h
AN: SM21C-07    [PDF]
TI: Alfv\'en Wave Modulation of Substorms and Outflowing O+ ions Observed by Cluster: Kinetic Features
AU: * Lee, E
EM: eslee@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, CA 94720 United States
AU: Parks, G K
AF: Space Sciences Laboratory, University of California, Berkeley, CA 94720 United States
AU: Wilber, M
AF: Space Sciences Laboratory, University of California, Berkeley, CA 94720 United States
AU: McFadden, J
AF: Space Sciences Laboratory, University of California, Berkeley, CA 94720 United States
AU: Dandouras, J
AF: CESR, CESR, Toulouse, 1111 France
AU: Reme, H
AF: CESR, CESR, Toulouse, 1111 France
AU: Sauvaud, J A
AF: CESR, CESR, Toulouse, 1111 France
AU: Bosqued, J
AF: CESR, CESR, Toulouse, 1111 France
AU: Kistler, L
AF: Space Sciences Laboratory, University of New Hampshire, Durham, NH 37024 United States
AU: Moebius, E
AF: Space Sciences Laboratory, University of New Hampshire, Durham, NH 37024 United States
AU: Klecker, B
AF: MPE, MPE, Garching, 1234 Germany
AU: Bavassano, M B
AF: IFSI, IFSI, Frascati, 1234 Italy
AU: Korth, A
AF: MPAE, MPAE, Lindau, 2345 Germany
AU: Lundin, R
AF: SISP, SISP, Kiruna, 23456 Sweden
AU: McCarthy, M
AF: Earth and Space Sciences, University of Washington, Seattle, WA 98195 United States
AB: The bulk parameter picture will now be expanded to provide a more comprehensive view of substorm dynamics in the geomagnetic tail. Phase space distributions of ions show presence of multiple component plasmas, H+ and O+. Both field-aligned unidirectional and bidirectional beams are observed at energies varying from a few hundred eV to $\approx$3 keV. The 2D cuts of the 3D distributions show very complex and highly time varying features. Extremely large gradients in the phase space occur with ions existing in one ${\bf v}_\perp$ quadrant and none in other quadrants. This yields large $\langle{\bf v}\rangle_\perp$ which can be falsely interpreted as flowing plasmas. What is actually happening is that the Cluster was remote sensing a nearby boundary. This is another example that shows using moments alone to characterize the plasma sheet can lead to misleading results. Using the 4 Cluster data, the current sheet thickness is estimated to be around $\approx$1000-2000 km. This thickness is comparable to the few keV ion Larmor radius. Both ionospheric and plasma sheet ions are observed in the current sheet indicating a strong MI coupling existed. These observations require kinetic interpretation and new kinetic models of substorms must be developed to explain them.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2471 Plasma waves and instabilities
DE: 2736 Magnetosphere/ionosphere interactions
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting