The first part of this project will be studying the physical and chemical processes associated with formation of thin metallic-ion structures in the very-high-latitude upper atmosphere. Experiments will be conducted at the incoherent-scatter radar facility at Sondrestrom, Greenland. The PI will use a routine measurement program (currently underway) to establish a database that characterizes different structures, such as single versus double layers, latitudinal and altitude distributions. He will also use a new experimental mode that simultaneously determines latitudinal variation of electric fields and high resolution density structures. In conjunction with a new numerical model, these data will investigate the relative roles of electric fields and neutral winds in layer formation, determine the effects of time-varying E-fields, and discover the effects of aeronomic parameters, such as the ion-neutral collision frequency. Secondly, the PI will further develop a new Eulerian 3-D time-dependent model of the polar ionosphere. This approach is advantageous to the traditional Lagrangian method in permitting efficient high spatial resolution, in turn allowing time-dependent studies of polar plasma structures and better comparisons with data. Using a new electric field model, the PI will investigate time-dependent ionospheric effects, particularly for northward interplanetary magnetic field (IMF) conditions. This model can determine the continuous ionospheric response to a time-varying IMF. He can then predict "space weather" effects, if appropriate IMF and space-particle data inputs are available to the model.
