Verification of role of ion viscosity for a transition to improved confinement mode in helical plasmas

我们在LHD和Heliotron-J上进行了电极偏置实验。通过在ECRH放电中施加三角波电压，成功地实现了负等离子体电阻的过渡。在前向跃迁中观察到储能的提高、密度涨落的抑制等表明禁闭改善的现象。正向跃迁和反向跃迁的阈值电压不同，在伏安-电流曲线上观察到了滞后现象。

We carried out electrode biasing experiments in the LHD and the Heliotron-J. The transition with the negative plasma resistance was successfully achieved during applying triangular-waveform voltage in ECRH discharges. The improvement of the stored energy, the depression of the density fluctuation and the other phenomena indicating the confinement improvement are observed in the forward transition. The threshold voltage was different between forward transition and backward one and the hysteresis was observed in the voltage-current curve.