Experimental results on the confinement and heating of the plasma in the TFR Tokamak

TFR is a Tokamak device (R=98cm; a=20cm; Bsub(T)=60kG; Isub(p)=400kA). The best plasma characteristics obtained with ohmic heating are: Tsub(e)=2,5keV; Tsub(i)=1,2keV; tau=20msec; n tau=2.1012 cm2s-1. The electron power balance involves three regions in the plasma: the central region, inside the q=1 magnetic surface, which is dominated by MHD internal disruptions; the gradient region, between the q=1 and q=2 magnetic surfaces, which is dominated by a non classical heat conductivity, interpreted by the dissipative trapped electron drift mode; the outer shell in which radiate the light impurities, and where the conduction is non classical. The ion power balance is still inaccurate; the ionic heat transport coefficient is about twice the neoclassical value. A powerful neutral heating (600kW - D0 or H0 - 35keV) increases the ion temperature up to 2keV and the plasma enters into the so called collisionless regime. The heating is homogeneous through the plasma section, and the ion temperature increases linearly with the neutral injected power. The non growth in electron temperature is unexplained yet