HR: 16:45h
AN: SH54A-04    [Abstracts]
TI: Using Plasma Convection to Observe Global Electric Fields in the Inner Magnetosphere
AU: * Jahn, J
EM: jjahn@swri.edu
AF: Southwest Research Institute, Space Science Department 6220 Culebra Road, San Antonio, TX 78238-5166 United States
AU: Samara, M
EM: msamara@swri.edu
AF: Southwest Research Institute, Space Science Department 6220 Culebra Road, San Antonio, TX 78238-5166 United States
AU: Henderson, M G
EM: mghenderson@lanl.gov
AF: Los Alamos National Laboratory, ISR-1 MS D466, Los Alamos, NM 87545 United States
AU: Thomsen, M F
EM: mthomsen@lanl.gov
AF: Los Alamos National Laboratory, ISR-1 MS D466, Los Alamos, NM 87545 United States
AU: Denton, M
EM: mhdenton@lanl.gov
AF: Los Alamos National Laboratory, ISR-1 MS D466, Los Alamos, NM 87545 United States
AU: Fok, M
EM: mei-ching.h.fok@nasa.gov
AF: Goddard Space Flight Center, NASA Goddard Space Flight Center MC 692 Greenbelt, MD 20771, Greenbelt, MD 20771 United States
AB: Solar wind driven large scale electric fields play an important role in the dynamics of the plasmasphere, the storm-time ring current, and the plasma sheet access to the inner magnetosphere. Local in situ measurements of the electric field provide a detailed yet highly localized picture. Global field maps, often derived by mapping out ionospheric measurements or models, may only inadequately predict or completely miss important field structures like SAPS. Medium to low energy plasma measurements (below a few keV) can be used to help bridge the gap between existing measurement and modeling techniques. We are presenting results from medium energy ENA imaging combined with in situ plasma measurements from the magnetosphere, ionosphere, and the solar wind as well as ground based ionospheric observations. We show that both in terms of spatial distribution and intensity ENA measurements show a remarkable sensitivity to the global electric field structure. We discuss two distinct sets of observations: (1) the sunward motion of the inner edge of the plasma sheet in response to periods of enhanced convection, (2) the long-term correlation between Kp and plasma content of the inner magnetosphere (predominantly plasma sheet material) derived from ENA measurements. We show that ENA observations are very sensitive to the global electric field and its changes, both in the sense of capturing the global plasma dynamics and in the sense of measuring the total amount of plasma delivered into the inner magnetosphere. The key to observing these effects lies in concentrating on particle energies low enough (below a few keV) such that the plasma motion is controlled by electric rather than magnetic fields.
DE: 2712 Electric fields (2411)
DE: 2720 Energetic particles: trapped
DE: 2730 Magnetosphere: inner
DE: 2760 Plasma convection (2463)
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005