In this thesis, I discuss two related but ultimately independent courses of experimental studies in nonneutral plasma physics. The first study considers a magnesium ion plasma by examining collisions and test particle transport under magnetized and correlated conditions; the second study considers a pure electron plasma by measuring a decay of plasma waves to longer wavelength. Both of these studies include a discussion of the experimental apparatus used therein.In the first study, I discuss collisional phenomena in a pure magnesium ion plasma and the techniques of selective spin-tagging diagnostics for the measurements of such phenomena. The experiment explores the effect of two important differences from binary collisions of bare charges: magnetization suppression, and correlation enhancement. Magnetization suppression occurs when the cyclotron orbit size rc becomes comparable to the distance of closest approach b, giving a reduction of approximately log(rc/b). In the opposite regime, lower temperatures quadratically increase the correlation parameter, and the same experiment shows that the collision rate increases as exp (−T). In the second study, I consider the decay of electron acoustic waves (EAWs) in a pure electron plasma. I begin this study with a discussion of Landau damping, which quickly filters out EAWs from most plasmas; however, at large amplitudes nonlinear effects perturb the velocity distribution in such a way that Landau damping is all but eliminated, allowing for extended observation of EAWs and their decay to longer-wavelength daughter waves. Interestingly, no lower threshold for decay is observed, but instead a change in regime occurs around a drive amplitude of 0.3V, below which the growth rate of daughter waves is generally constant. For drive amplitudes above about 1V, simple decay is absent, but instead “ringing” is observed at several higher harmonics, which exhibit frequency growth due to heating effects.