Ion temperature measurements in JT-60 plasmas by active beam scattering

The active beam scattering method was applied to ion temperature measurements in JT-60 plasmas. The ion temperature found was in reasonable agreement with that obtained from Doppler broadening of the Ti XXI and Ti XXII resonance lines in the temperature range of 1.5 to 10 keV. With the help of the scattering system, the central ion temperature of JT-60 plasmas during 40 keV and 70-75 keV NBI heating was measured. Higher ion temperature was obtained during 70 to 75 keV than during 40 keV NBI heating. These data and a possible explanation are presented. A numerical simulation of this diagnostic indicates that the ion temperature as deduced from the diagnostic is almost equal to the bulk temperature when the ratio of high energy ion component to the total ion stored energy is less than 0.3.