Thomson Scattering Measurement of Two Electron Temperature Components in Transition to Detached Plasmas

We have performed laser Thomson scattering (LTS) measurements during the transition between attached and detached helium plasmas in the linear divertor simulator NAGDIS-II. In the detached plasma, the LTS spectrum shows a discrepancy with a single Gaussian function. The discrepancy is resolved by the spectrum fitting with a sum of two Gaussian functions, indicating that the electron energy distribution contains two different temperature components. (C) 2018 The Japan Society of Plasma Science and Nuclear Fusion Research