43 Years of fun basic plasma experiments

Summary form only given. This talk will present an overview of some of the most enjoyable low-temperature plasma experiments I have carried out with my students over the course of my career. It will begin with the connection between solitons and the Schrödinger equation, and continued with the discovery of cylindrical and spherical soliton-like structures. From moving structures we will progress to stable ones: sheaths and double layers. Where do double layers form? How can we measure double layer potentials? These questions lead to the development of emissive probe techniques. From there we will move on to the Bohm criterion and the first measurements of the full plasma potential variations of sheaths and presheaths in a single-species plasma, and later in two-ion-species plasmas. Finally, our recent measurements of double layers and presheaths in uniform helicon plasma will be presented, which address the earlier unresolved question of where double layers form.