Simultaneous measurement of electron and ion temperatures with helium-like argon spectrum

The helium-like argon spectrum is measured for the plasma in the Large Helical Device (LHD). The electron temperature Te derived from the intensity ratio of the resonance line (1s2 S0 – 1s2p P1) to a dielectronic satellite line (1s22p P1/2 – 1s2p2 D3/2) is consistent with the central Te measured with the Thomson scattering method when the electron density ne has a peaked profile. The ion temperature Ti is simultaneously determined from the Doppler broadening width of the resonance line and the establishment of thermal equipartition between electrons and ions, i.e., Ti = Te, due to the increase of ne is experimentally confirmed.