This grant supports Dr. Gombosi's efforts at modeling the environments of comets. The main thrust of the work will be the further development of a time-dependent, multidimensional dusty model of the inner coma. In addition, new models of the nucleus- coma interface, the radiative transfer processes, as well as the plasma environment of the comet will be developed. The historic encounters with comets Halley and Giacobini-Zinner have begun to lead to a better understanding of the major physical and chemical processes controlling cometary environments. The quantitative and qualitative leap of available information paved the road to a new generation of comprehensive comet models, which will synthesize our knowledge in such diverse areas as nucleus formation, orbital evolution, gas and dust emission, dynamics and aeronomy of partially ionized dusty gas flows, and solar wind interaction. A new generation of cometary models will evolve from a series of intitiatives by various groups and individuals simultaneously cooperating and competing. Dr. Gombosi will be an active participant in this effort.
