A Neutral Beam Probe (NBP) was developed for studying the Texas Helimak plasma experiment. The probe consisted of a beam of neutral sodium atoms that were injected into the magnetized plasma of the Helimak. After some fraction of the atoms underwent electron impact ionization, the resulting ion beam followed a path to an energy analyzer where the change of energy was detected along with the total ion current. The measurement of the change of energy implies a change of potential energy at the point of ionization since all the neutral beam particles enter the plasma with a well determined energy. The total current detected at the energy analyzer also implies a rate of electron impact ionization, which in turn implies an electron density and temperature. The NBP was developed based on the Elmo Bumpy Torus (EBT) Heavy Ion Beam Probe (HIBP), which was operated at Oak Ridge National Labs. In fact, the majority of the equipment that was used in this experiment was taken from that HIBP, and some of it was rebuilt. We generated an estimate of the radial electric field in the Helimak along with an estimate of density changes as a result of biasing experiments. Interestingly, when a bias voltage was applied inside the Helimak, the radial electric field did not change significantly at the sample region, but the electron density did vary. The probe data taken by the Helimak team agree with the density changes. The electric field derived from Langmuir probes is not trivial (especially in plasmas with flows) and was not computed for this thesis. / text

The doctoral thesis presents the diagnostic neutral lithium beam on the COMPASS tokamak in Prague. The technical part describes the system for injection of accelerated lithium beam into the COMPASS tokamak and the respective detection systems for beam emission spectroscopy. The physical part describes the analysis of measured spectroscopic data, with particular emphasis on density fluctuations in the edge plasma. Detailed analysis of turbulent structures outside of the confined plasma region is presented, as well as investigations of the ELM instabilities during high confinement mode plasma operation. The thesis also presents the development and proof-of-concept measurements of a new and unique diagnostic method - atomic beam probe. The method uses detection of the ionized part of the beam for current density profile measurements in the plasma edge.