Modeling Astrophysical Disks Using Nearest Neighbor Perturbations

ii ABSTRACT A new way to model astrophysical disks based on nearest neighbor perturbations (NNPs) is presented. Key aspects of the NNP model are: chopping up space into a hexagonal grid, imposing differential rotation (as opposed to letting it arise naturally), treating the boundaries as reservoirs, and making the system independent of scale. A Fortran program was written to test the model. The algorithm was fast, and calculations using 10 5 particles could be run on a microcomputer. Simulations of disks with different masses were carried out. The driving force of the model was accretion. The rate of accretion was dependent on the amount of mass in the disk. Spiral arms and ringlet phenomena were observed. The type of pattern depended on the mass in the disk. iii ACKNOWLEDGEMENTS Foremost, I would like to thank my advisor Prof. Robert Chambers for his time and patience. I would also like to thank: Prof. Catalin Mitescu for his help with the programming aspects of the this project, the Geology Department for the use of their computer facilities, Dr. John Hackwell for sparking my interest in disks and nebula, and Prof. Alexandre Chorin for introducing me to the topic of computational physics.