Pellet injection experiments of ECH plasmas on Heliotron E

Deuterium pellet injection is used for investigation of transport of Heliotron E plasmas through a dynamic process. With an ECH (electron cyclotron heating) heated plasma as a target plasma, such conditions as auxiliary toroidal field control, magnetic axis shift, and externally added magnetic field perturbation are studied. Among various magnetic axis positions from δ_v=-60 mm to δ_v=+35 mm, cases from δ_v=-40 mm to δ_v=0 mm are found to be good for confinement. In the gas puffed case, δ_v=-20 mm was optimum. In the case of α*=0.05 and δ_v=-20 mm, the ECH plasma seems optimum. The line-averaged density in the central chord after pellet injection is kept constant even without gas puffing in contrast with cases of α*=0.0. In the experiments on magnetic field disturbance, only a small difference between MI=0% and MI=100% under the standard configuration is observed, which is consistent with the results obtained by gas puffing