RETRACTED ARTICLE: Review on Plasma Edge Analysis Using the Auto-Correlation and Probability Distributions of Fluctuations

Abstract

We have reviewed the plasma edge fluctuations analysis over a wide range of plasma and field parameters in the IR-T1 tokamak. Fluctuation levels and spectra were measured using two arrays of Langmuir probes on the edge region. Under almost all conditions the edge plasma was turbulently unstable, with a broadband fluctuation spectrum in the drift wave range of frequencies f = 10-1000 kHz. A stable state was observed only in the very cold, low-current discharge formed at unusually high neutral filling pressure. Otherwise, the relative fluctuation level as monitored by the ion saturation current was very high while the fluctuation power spectra were roughly invariant in shape. The relative fluctuation level was always highest near the wall and decreased monotonically toward the plasma centre.