Peculiarities of electrode biasing experiments on the T-10 tokamak in regimes with Ohmic and ECR heating

Two types of electrode biasing H-mode were observed on the T-10 tokamak in regimes with electron–cyclotron resonant heating (ECRH). These types differ mainly by the dynamics of the electron temperature. Both types are characterized by a strong (130 V cm−1) radial electric field formation, a decrease of Dα emission intensity, a rise of line-average plasma density and an increase in energy confinement time. However, distinguishing features of the type II H-mode are a time delay of 70–80 ms in the electron temperature growth, a slower increase of the plasma density, and a weak drop of Dα intensity. The differences between the two types of biased H-mode are likely to be connected with the conditioning of the vacuum chamber.