Self-organized criticality properties of the turbulence-induced particle flux at the plasma edge of the HT-6M tokamak

The power spectrum and the probability distribution function (PDF) of the t urbulence-induced particle flux Gamma in the velocity shear layer of the HT -GM edge region have been measured and analysed. Three regions of frequency dependence (f(0), f(-1), f(-4)) have been observed in the spectrum of the Awe. The PDF of the flux displays a Gamma (-1) scaling over one decade in G amma. Using the rescaled-range statistical technique, we find that the degr ee of the self-similarity (Hurst exponent) of the particle flux in the meas ured region ranges from 0.64 to 0.83. All of these results may mean that th e plasma transport is in a state characterized by self-organized criticalit y.