HR: 14:25h
AN: SA23B-03 INVITED     [Abstracts]
TI: Polar IT Science and its Coupling: A Broad Perspective from a Narrow View
AU: * Thayer, J P
EM: jeffrey.thayer@colorado.edu
AF: University of Colorado, Aerospace Engineering Sciences Dept. UCB 429, Boulder, CO 80309-0429
AB: The coupling of the thermosphere with the ionosphere, and ultimately with the magnetosphere, in the polar regions is strongly height dependent. Below 200 km altitude, vertical and horizontal gradients persist in almost every basic property describing the thermospheric neutral gas and ionospheric plasma. For example in the vertical, ion motion can decrease in magnitude from 1500 m/sec to 200 m/sec, ion temperatures can decrease from 2000 K to 500 K, and neutral densities can increase by a factor of 10 over a 30 kilometer altitude range in the E-region. Horizontal gradients can be of much greater magnitude. Sources of energy are required to sustain these structures in the neutral gas and plasma, and, once created, these structures can lead to a redistribution of energy, mass and momentum. Observations of E-region property gradients and energy transfer have been extremely limited but are fundamental to the physics of the region. Furthermore, this region is central to understanding the electrodynamic coupling that occurs between the ionosphere and the magnetosphere. Here, incoherent scatter radar measurements are presented to illustrate the E-region structures observed within the limited horizontal coverage provided by the radar, while taking the broader perspective of how these structures occur throughout the polar E-region and how they impact M-I coupling. Future spacecraft missions targeted to study this region of the ionosphere are needed to regularly observe the energy flux into the region and resolve property gradients. The Geospace Electrodynamic Connections mission is the next step to achieving this goal.
DE: 2409 Current systems (2721)
DE: 2411 Electric fields (2712)
DE: 2427 Ionosphere/atmosphere interactions (0335)
DE: 2467 Plasma temperature and density
DE: 3369 Thermospheric dynamics (0358)
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005