Model on L- to H-Mode Transition Driven with Lower-Hybrid Wave

In this letter, a model for active suppressing tokamak edge turbulence and hence inducing the L-mode to H-mode transition with lower-hybrid wave (LHW) is proposed. The model includes the two contents: (a) The poloidal sheared flow of plasma is generated by the ponderomotive potential and induced magnetization acting on a tokamak plasma resulting from the oscillating electric field of the injected LHW. (b) During the time the LHW is injected into tokamak edge, the edge turbulence and the LHW-generated plasma poloidal flow compete with each other; if the shear of plasma poloidal flow is large enough to suppress the edge turbulence, the confinement will be remarkably improved and hence the system will enter the H operating mode. This model leads us to find that the threshold LHW power required for edge-turbulence suppression is proportional to A(ω) ≡ (ω / ω_LH )² |(ω / ω_LH )²-1|, which enables us to explain the experiment in the JT-60 tokamak with lower-hybrid current drive.