Temporal behavior of the electron density profile during limiter biasing in the HYBTOK-II tokamak

A rapid change in the detailed edge electron density profile during positively biased limiter experiment is obtained with high temporal resolution of ∼20 μs using a laser blow-off lithium beam probe technique in HYBTOK-II tokamak. The transient change in the electron density profile and the movement of the position where a steep density gradient is formed are experimentally observed. The temporal behavior of the electron density profile correlates well with reductions in the biasing current and Hα emission in the scrape-off layer, and the suppression of electrostatic fluctuations near the edge of the core region. (author)