Recent Directions in Sheath Theory Inspired by Prof. Hershkowitz

This talk will recount the author’s introduction to plasma physics through experiments on sheaths in Prof. Hershkowitz’s laboratory and how it inspired theoretical research. Three topics will be discussed: the role of global confinement conditions on determining sheath structure, the role of electrostatic instabilities in determining how a plasma interacts with a material, and the unconventional electron and fireball sheaths found near positively biased electrodes. All of these examples remain current topics of research interest and were significantly influenced by Prof. Hershkowitz’s pioneering contributions. The importance of feedback between experiment and theory in order to advance scientific understanding was something that he stressed. It remains essential.