Toroidicity effects in electrostatic drift wave turbulence in tokamaks: Pt. 2

The concept of clumps is used in the Tokamak turbulence theory. Using the Misguich Balescu stochastic orbit treatment, the two-point fluctuation correlation equation is studied in detail. It is shown that the Hirshman-Molvig effect has a special influence on the clumps theory: the general quasi-linear diffusion regime does not exist in Tokamaks. It is found that the clumps cannot be considered only as a destabilizing mechanism ('clumps-induced instability'), the presence of Δω (the frequency width at fixed wavenumber) stabilizes the plasma. It is also shown that Δω ∼ ωsub(c) > ω as a result of the Hirshman-Molvig effect on the propagator. In this paper, the saturation appears as a result of the balance between the clumps and the ion Compton scattering. The fluctuation spectrum is estimated, the large Ksub(θ) asymptotic form is ksub(θ)sup(-10/3). (author)