Investigation of Turbulent Transport in Non-Stabilized Plasma at the Edge of the GOLEM Tokamak

Plasma turbulent transport at the edge of the GOLEM tokamak is investigated. For this purpose, ion saturation current (which is proportional to plasma density) fluctuations are measured by means of the Langmuir probe. Plasma stabilization was not activated during the discharges studied. Intermittent bursts of plasma density are observed. These bursts appear as a result of plasma turbulent transport processes, during which various coherent turbulent structures emerge and move. Such processes impede controlled thermonuclear fusion – they degrade plasma confinement and cause high heat load on the vacuum chamber walls and other plasma facing components, as well as their severe erosion together with unwanted capture of tritium. Therefore, investigation of plasma turbulent transport processes and dynamics of coherent turbulent structures is one of the most important problems to be solved on the way toward implementation of controlled thermonuclear fusion. The statistical and temporal characteristics of intermittent bursts of plasma density together with their radial dependence have been studied. It can be concluded from the study results that non-elongated blob-like structures with comparable sizes in the radial and poloidal directions should govern the plasma transport at the edge of the GOLEM tokamak.