Session AB - Astronomy and Space Physics.
MIXED session, Friday morning, October 05
SWR L1, Sid W. Richardson Building
In the upper atmosphere charged and neutral particles interact with each other and affect the dynamics and density distributions of each species. The charged particles are highly magnetized with motions perpendicular to the magnetic field dominated by electric fields and motions along the magnetic field influenced by pressure gradients and collisions with neutral gas. The neutral gas motion is dominated by heat sources from the Sun and the magnetosphere, and modified by collisions with ions. Large changes in the charged particle distributions occur from day to night leading to a charged particle layer in the ionosphere that is unstable to gravitational over-turning. The resulting instabilities are detrimental to the performance of space-ground radio communications. We will describe how a new observation program will increase our understanding of coupled ion-neutral motions in the upper atmosphere and thus our ability to specify and predict when and where plasma instabilities will occur.