Probe diagnostics in the edge of kstar tokamak plasma using fast floating harmonic method

Abstract

Summary form only given. Diagnostic of the edge region, called scrape-off layer (SOL) of tokamak plasma is of great interest because the research on the SOL plays an important role in understanding discharge characteristics between the plasma facing components and core region. For this reason, plasma diagnostics have been developed and adapted to the fusion plasma with high time resolution and small perturbation. Recently, Chung and co-worker [Lee et al, J. Appl. Phys. 101, 033305 (2007)] have developed a floating harmonic method that could measure plasma parameters, such as plasma density (or ion flux) and electron temperature without disturbing plasma, even in reactive plasmas which causes deposition on the probe. We have improved the floating harmonic method for more fast acquisition to utilize the diagnostic for tokamak plasmas. The ion flux and electron temperature were measured at far SOL region and compared with both interferometer and electron cyclotron emission (ECE) diagnostics. Our preliminary results show similar trend with that of interferometer and the ECE, which indicates that our method can be applied as a diagnostic for fusion plasma and the behavior of the edge plasma such as Edge Localized Mode (ELM) can be seen from the measurement.