Recent experiment progress on the HL-1M tokamak

Experiments on the auxiliary heating, fueling of plasma and wall conditioning were carried out on HL-1M. ECRH experiments were conducted successfully with Te increase more than 50%. The double sawtooth in soft X-ray radiation were observed, which imply that the reversed magnetic shear could be formed during ECRH. An eight-shot pellet injector (PI) was used for experiments. After the pellet injection, a hollow electron temperature and peaked density profile were obtained, accompanied with the increase of energy confinement time. The pellet ablation process was investigated with a CCD camera and an H.. emission detector array. Obviously asymmetry in the pellet cloud was observed in both the toroidal and poloidal direction. It is found that the velocity of pellet is slowed down obviously after the pellet enters into the plasma. The safety-factor q-profile was estimated with the inclination angle of ablation cloud with respect to the torus. Density limit investigations have been performed at different wall condition with three kinds of fuelling methods. It is found that higher density limit can be achieved in following conditions: one is the strong reduction of the impurity content after siliconization, another is the peaked density profile with pellet injection and/or SMBI. With a NBI system of 1MW, preliminary results of NBI experiments were obtained with increase of ion temperature from 600eV to 800eV. (author)