HR: 0800h
AN: SA51A-1126    [Abstracts]
TI: Thermospheric Response to Ion Heating in the Dayside Cusp
AU: * Demars, H G
EM: howard@aros.net
AF: Utah State University, Center for Atmospheric and Space Sciences, 4405 Old Main Hill, Logan, UT 84322-4405 United States
AU: Schunk, R W
EM: schunk@cc.usu.edu
AF: Utah State University, Center for Atmospheric and Space Sciences, 4405 Old Main Hill, Logan, UT 84322-4405 United States
AB: Recent satellite observations reveal that a neutral density enhancement of up to a factor of two can occur in the northern dayside cusp region at 400 km altitude. It has been suggested that Joule heating is responsible for the thermospheric upwelling. In order to quantify the magnitude of ionospheric heating necessary to cause the observed neutral density enhancement, we have conducted simulations using a global time-dependent model of the thermosphere together with an idealized heat source in the region of the cusp. In our simulations, we have varied the magnitude of the energy transfer to the thermosphere from the idealized heat source, the duration of the energy transfer, and the extent of the region in which the transfer occurs. We find that the energy transfer from the ionosphere to the thermosphere required to account for the observed neutral upwelling is considerable, on the order of 100 times the normal ion-neutral frictional heating expected at 400 km altitude.
DE: 2427 Ionosphere/atmosphere interactions (0335)
DE: 3367 Theoretical modeling
DE: 3369 Thermospheric dynamics (0358)
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005