Coagulation rates in the protoplanetary nebula: The effect of asymmetric dust grain charging

This dissertation examines the interaction of plasma and dielectric dust grains. It studies how dust grains charge and how asymmetric charge distributions develop under flowing plasma conditions. It reports on the discovery that dipole charge distributions develop when dielectric dust grains are exposed to flowing plasma. The results of this work are then parameterized and used in a study of how charged dust grains collide.; Collision cross sections (with sticking coefficients set to 1) are evaluated for several situations including the results of the parameterized charging model. It is discovered that dust grain charging from flowing plasma can enhance the collisional cross section compared with geometrical interactions. Additionally, a radius selection process is discovered that controls the cross sectional enhancements.; The cross section results are then incorporated into an analysis of coagulation in the protoplanetary nebula. It is discovered that the enhanced cross sections lead to increases in the coagulation rates for dust grains under certain conditions. A heuristic model applying the results from the numerical studies is then provided. This model modifies existing models of dust coagulation in the protoplanetary nebula to incorporate the new coagulation enhancing results.; It is presumed that the enhancements in coagulation could provide possible explanations for certain observations associated with protoplanetary nebulae that existing models cannot explain. These problems are related to chondrules and chondrites. From observations, chondrites, which are composed of chondrules and matrix material, have a complimentary relationship in the depletion and enhancement of certain volatile elements. Additionally, chondrules are tightly constrained to one millimeter in size while matrix and rim material is constrained to a micron. The segregation and enhancement relationships discovered from the coagulation study are provided as possible explanations for these phenomena.