Stochastic instability and turbulent transport. Characteristic scales, increments, and diffusion coefficients

Stochastic instability and its associated turbulent diffusion models are reviewed, with particular attention given to the problem of obtaining estimates and scaling laws that characterize correlation effects and increments. Specific models considered include the quasilinear Kazantsev approximation, stochasticity in a system of convective cells, the Kadomtsev–Pogutse scaling, percolation models, and the Rochester–Rosenbluth balance. The primary goal is to highlight the importance of determining the functional dependence of the stochastic instability increments and transport coefficients on turbulent pulsation amplitudes and other key parameters (characteristic pulsation frequencies, drift velocities, spectral energy flow, etc.) describing the systems under discussion.