Investigation of the H-mode during ECRH in the T-10 tokamak

An improved confinement regime with an external transport barrier (H-mode) is obtained during electron-cyclotron resonance heating of a plasma in the T-10 tokamak. A characteristic feature of this regime is a spontaneous density growth accompanied by a drop in the intensity of Dα line and an increase in βp by a factor of ∼1.6. The threshold power for the L-H transition is close to that predicted by the ITER scaling. The best characteristics of the H-mode are achieved with decreasing qL to 2.2. It is shown that the external transport barrier arises for electrons, whereas the heat transport barrier insignificantly contributes to improved confinement.