I have morethan the usual number of people to thank for their assistance during my stay at Caltech-and for my staying here at all. We all remember the War, the Draft, and the Great Draft Lottery of 1969: I lost the lottery, but (as most of the white, educated middle class did) avoided the War. Prof. M. Cohen, my first mentor, assisted me in getting a job at JPL. Prof. Ward Whaling has spent the last four years bending rules in my favor so I could keep the job. To both I am grateful. Many people at J7L have helped me in the course of this work. I would especially like to thank Don Trask and Pete MxcDoran for theirs assistance and encouragement.The data for this thesis would not have existed without the hard work of Warren Martin and Art Zygielbaum. I also thank Jack Lorell of the Mariner Mars 1971 Celestial Mechanics Experiment for assisting me in obtaining the data from that mission. I am indebted to Dorothe Horttor of JPL who has worked beyond the call of duty typing the thesis for me. I have benefitted greatly from my association with my advisor Prof. J. R. Jokipii. His comments on this manuscript were extremely valuable in making it coherent and readable. I aFso thank Prof. D. 0. Muhlemn for his comments. Profs. James Gunn and PeterGoldreich have done much to stimulate my learning about astrophysics; I thank them for their patience, Many friends have made my stay at Caltech more pleasant. I especially thank Paul Schechter for his companionship and for taking a date to the prty where I met my wife, Judy. She deserves specialcredit for keeping me sane and happy enough to finish this endeavor. During the course of my graduate study I have been supporte
