Progress in LHD Experiment

In the third campaign (O7.13.99-12.14.99), NBI (<4.2 MW), ICRH (<1.4 MW) and ECRH (<0.9 MW) were used to heat the plasma in LHD. The carbon tiles were installed as divertor plates, resulting in significant reduction in metal impurity concentration (Fe). The maximum field used in the experiment is 2.gT.IJpgrading of the key hardware systems led to (i) higher T" [T,(0) = 4.4keY atn"= J.J x 1018m3 and Po6, = 1.8 Mwl, (ii) higher confinement [%= 0.3 s, Z"(0) = l.l keV at n"(0) = 6.5 x l0re m-3 and Po6, = 2.0 MWl, (iiD higher stored energy W, = 880 kJ, (iv) higher volume averaged B = 2.4Eo (at B = 1.3 T). The temperature pedestal enhances the confinement significantly (50Ea higher than the ISS95 scaling). The ICRH heating was found to be as efficient as NBI heating. Long pulse discharges (80 sec NBI shot, 68 sec ICRH shot) have been achieved without any technical difficulty.