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Low-Energy Electron Effects on the Polar Wind Observed by the POLAR SpacecraftLarge ion outflow velocity variation at POLAR apogee have been observed. The observed H+ flow velocities were in the range of 23-110 km/s and 0+ flow velocities were in the range of 5-25 km/s. These velocity ranges lie between those predicted by simulations of the photoelectron-driven polar wind and "baseline" polar wind. The electric current contributions of the photoelectrons and polar rain are expected to control the size and altitude of an electric potential drop which accelerates the polar wind at relatively high altitudes. In this presentation, we compare polar wind characteristics observed near 5000 km and 8 RE altitudes by the Thermal Ion Dynamics Experiment (TIDE) with measurements of low-energy electrons sampled by HYDRA, both from the POLAR spacecraft, to examine possible effects of the polar rain and photoelectrons on the polar wind. Both correlations and anti-correlations are found between the polar wind velocities and the polar rain fluxes at POLAR apogee during different polar cap crossings. Also, the low-altitude upward/downward photoelectron spectra are used to estimates the potential drops above the spacecraft. We interpret these observations in terms of the effects that both photoelectrons and polar rain may have on the electric potential and polar wind acceleration along polar cap magnetic field lines.
Document ID
20000004593
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Horwitz, J. L.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Su, Y.-J.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Dors, E. E.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Moore, Thomas E.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Giles, Barbara L.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Chandler, Michael O.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Craven, Paul D.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Chang, S.-W.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Scudder, J.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1998
Subject Category
Astronomy
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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