Self-sustained turbulence and H-mode confinement in toroidal plasmas

The method of self-sustained turbulence is applied to the tokamak plasma, incorporating the effect of an inhomogeneous radial electric field. The transport coefficient is derived, making a bridge between L- and H-phase plasmas. It is possible to construct a unified transport model of the L- and H-mode phases. The anomalous transport coefficients are obtained in a unified and explicit form in terms of profile parameters such as the plasma pressure gradient, the magnetic shear, the shear and curvature of the radial electric field. Strong reductions of the thermal conductivity, χ, the electron and ion viscosities, μe, and μ, and the turbulent level in the H-phase plasma are explained. Furthermore, an additional stability window due to E'r is discovered in the higher pressure-gradient regime. The anomalous ion viscosity determines Δ, the typical scale length or Er. Self-consistent solutions of Δ and μ are discussed. (author)