HR: 0800h
AN: SA51B-0518    [Abstracts]
TI: Polar E-Region Thermospheric Properties from Ion Motion Characteristics
AU: * Wiren, A
EM: ashley.wiren@colorado.edu
AF: Aerospace Engineering Sciences, University of Colorado, 431 UCB, Boulder, CO 80309, United States
AU: Thayer, J
EM: jeffrey.thayer@colorado.edu
AF: Aerospace Engineering Sciences, University of Colorado, 431 UCB, Boulder, CO 80309, United States
AU: Heinselman, C
EM: craig.heinselman@sri.com
AF: Center for Geospace Studies, SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025, United States
AU: Deng, Y
EM: ydeng@ucar.edu
AF: High Altitude Observatory, National Center for Atmospheric Research, 3080 Center Green, Boulder, CO 80309, United States
AB: The ion motion in the polar ionosphere deviates from the E × B plasma drift motion with descending altitude as the neutral gas density and wind exert a greater influence. The neutral gas density imposes a drag force on the ions resulting in a decrease in the ion velocity magnitude and a rotation of the ion velocity vector towards the local electric field direction. The neutral wind also affects the ion velocity in the E-region but in a less predictable manner. High-latitude incoherent scatter radar observations of ion motion indicate, at times, that the E-region ion speed can exceed the F-region E × B drift speed. This can be attributed to neutral winds. The accompanied observation of ion temperature profiles, when used with the observed ion velocity, also show vertical structure that can be attributed to neutral winds. Data from the incoherent scatter radars of Sondrestrom, Poker Flat, and EISCAT Svalbard are used to isolate contributions from the neutral gas density and winds and, in particular, to investigate the ionospheric conditions surrounding enhanced ion speed in the E-region. A global ionosphere thermosphere model (GITM) will demonstrate the impact of the thermospheric gas on the ion motion and separate the effects due to neutral gas density and wind.
DE: 2407 Auroral ionosphere (2704)
DE: 2437 Ionospheric dynamics
DE: 2467 Plasma temperature and density
SC: SPA-Aeronomy [SA]
MN: 2007 Fall Meeting