HR: 13:45h
AN: SM53D-01 INVITED    [Abstracts]
TI: The Role of Electromagnetic Waves in Magnetosphere-Ionosphere Coupling
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
AU: Zhu, L
EM: zhu@cc.usu.edu
AF: Utah State University, Center for Atmospheric and Space Sciences 4405 Old Main Hill, Logan, UT 84322-4405, United States
AU: Sojka, J J
EM: fasojka@sojka.cass.usu.edu
AF: Utah State University, Center for Atmospheric and Space Sciences 4405 Old Main Hill, Logan, UT 84322-4405, United States
AB: Electrodynamics plays an important role in Magnetosphere-Ionosphere (M-I) coupling at high latitudes. Changes in the dynamic pressure of the solar wind and the Interplanetary Magnetic Field lead to changes in the electric fields, currents, and conductivities that link the magnetosphere and ionosphere. The changes are initiated by Alfven waves that propagate along the magnetic field from the magnetosphere to the ionosphere. However, the ionosphere plays an active role and as the ionospheric plasma density changes in response to electron precipitation, Alfven waves are launched from the ionosphere that act to change the electric fields and currents linking the two regions. The net effect is that small-scale plasma structures are created, particularly during substorms. During the substorm expansion phase, there are spatially separated small-scale electron and ion temperature hot spots, localized regions of downward plasma velocity, and regions where NO+ is a dominant F- region ion. Electromagnetic waves also play an important role in the formation of sun-aligned polar cap arcs. In addition, electromagnetic wave turbulence is prevalent at high altitudes above the polar cap and it could have an important effect on the polar wind.
DE: 2400 IONOSPHERE (6929)
DE: 2483 Wave/particle interactions (7867)
DE: 2736 Magnetosphere/ionosphere interactions (2431)
DE: 2790 Substorms
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting