Statistical analysis of turbulent flux and intermittency in the nonfusion magnetoplasma Blaamann

Turbulent particle flux due to correlated fluctuations of density and E(vector sign)xB(vector sign)-drift velocity has been statistically characterized in the simple magnetized torus Blaamann [F. J. Oeynes, O. M. Olsen, H. L. Pecseli, A. Fredriksen, and K. Rypdal, Phys. Rev. E 57, 2242 (1998)]. The shape and width of the probability distribution functions (PDF) and how they change as a function of time resolution τ upon coarse-graining have been analyzed. The shape of the PDF is non-Gaussian with a sharp central peak and is strongly asymmetric. The resulting width, σ, scales as a power-law over about two decades in τ, σ∼τH, for τ>100 μs. As τ decreases the width tends to flatten, i.e., the effective Hurst exponent H increases continuously in the interval 0.5<H<1. The behavior of the PDF at small time scales seems to be ascribed to the presence of coherent structures, living in the torus generated by flux instability