1.6 The Pellet Enhanced Performance on the HL-2A Tokamak ①

Improved confinement during the fuelling is one of the most important subjects for the tokamak research. Experiments have confirmed that anomalous transport is caused by turbulences driven by temperature and density gradient in plasma. Pellet injection is not only an important fuelling method, but also is an efficient tool for controlling the plasma pressure and current profile. The improved energy confinement has been observed in many tokamaks with center pellet injection since 1980’s. The pellet enhanced performance (PEP)was achieved with high power auxiliary heating in JET and other large tokamaks~. In general, the peaked density profile, E×B shear and weak or reversed magnetic shear are thought to be crucial causes for the low transport of the plasma. In this paper we report the pellet injection experiment results without auxiliary heating on HL-2A tokamak. Our works focus on the investigation of the electron heat transport in ohmic discharges with center pellet fuelling.