There are indications that the dominant source of plasma for the plasma sheet and the near-Earth portion of the magnetosphere may be the ionosphere. Over the past two decades there have been numerous investigations involving spacecraft observations, radar observations, and simulations directed toward understanding the possible mechanisms that drive the upward/outward ionospheric plasma flow observed in the high-latitude F region above 500 km altitude.
A good empirical model has not been generated for the outflow (inflow) of plasma from (to) the auroral zone and polar cap as a function of geomagnetic activity, solar activity, and season. This proposal seeks to address this latter issue through the utilization of ion flow data from the Defense Meteorological Satellite Program (DMSP) series of spacecraft, flying in the topside F region at the 800 km altitude level. The database from these high duty cycle spacecraft observations extends from 1987 to the present, covering more than a complete solar cycle.
Major proposed tasks in performing this research are 1) the determination of the seasonal variation in the plasma outflow in the topside F region, 2) investigation of the baseline values of the outflux and velocity structure and of the magnitude of storm-time perturbations in the plasma outflow, 3) performing a superposed epoch analysis to establish the characteristic response of the ionosphere to changes in magnetic activity, and 4) development of an analytic model of plasma outflow suitable for use by the general scientific community.
