SOME CHARACTERISTICS OF MIDLATITUDE F LAYER STORMS GENERATED BY THERMOSPHERE - PLASMASPHERE COUPLING PROCESSES.

摘要

In this dissertation, I interpret calculations that I made to describe stormtime variations in equinoctial dayside plasma parameters when the variations are primarily caused by processes dependent upon collisional coupling between the thermosphere and the plasmasphere. The calculations are made with a computer model formed by linking two theoretical models: a pre-existing thermospheric model that describes dayside variations in thermospheric parameters during stormtime heating of the thermosphere; a plasmaspheric model which I developed to describe dayside plasmaspheric variations caused by the thermospheric variations described by the thermospheric model and by variations in a magnetospheric electric field. Both portions of the computerized storm model solve partial differential equations describing conservation of species, momentum, and energy by replacing dependent variables with expansions in time series. The thermospheric portion of the storm model solves for variations in gas temperature, horizontal wind velocity, and densities of atomic oxygen and molecular nitrogen while the plasmaspheric portion of the storm model solves for variations in ion densities of oxygen and hydrogen, ion fluxes of oxygen and hydrogen, temperatures of ions and electrons, and heat fluxes through ions and electrons. I summarize other calculations that have been used to describe variations in thermospheric and plasmaspheric parameters and note the advantages and limitations of the model calculations used to obtain results presented in this dissertation. The most significant result from my calculations is the distinction shown between temporal and spatial variations in the ion densities of oxygen and hydrogen during the evolution of an F layer storm. The distinction is latitude and altitude dependent and results from differences in the ion chemistry and altitude distributions of the ions of oxygen and hydrogen. Another important result of my investigation is the increase in calculated dayside losses of hydrogen ions when the strength of a magnetospheric electric field is increased. My calculations apply to the dayside topside plasmasphere at equinox along goemagnetic field lines that intersect Earth between geomagnetic latitudes 20(DEGREES)N-60(DEGREES)N. Recognizing the limitations of the model, I use calculations describing thermosphere-plasmasphere processes discussed in this dissertation to infer physical processes responsible for plasmaspheric variations detected from spacecraft during a specific F layer storm.