Discharge plasma processes of ring-cusp ion thrusters

iii Since it is difficult to rank the importance of all the wonderful people that helped with this dissertation, I present my acknowledgements in chronological order. First and foremost, I thank my wife, Kristi Wirz, for her amazing support and patience through this process, and for being the best friend I have ever had. My JPL advisor and friend, Jay Polk, introduced me to the intoxicating world of advanced propulsion and my Caltech advisor, Fred Culick, gave me the freedom to follow an unbeaten path with my research. Juergen Mueller introduced me to micropropulsion and has been a great person to work with through these years and hopefully many to come. Colleen Marrese helped and supported me when I was fresh and ignorant and taught me the ins and outs of an electric propulsion laboratory. Al Owens taught me how to work in the metal machine shop to make vital parts for my research (without killing myself). John Ziemer has been a great friend and mentor and had the pleasure of helping me completely dismantle my vacuum system and develop computer controlled plume diagnostics. Rob Kolasinski has been in the trenches with me through the early days of the “wonderful ” first year at Caltech and has helped me immensely in the lab.