Bursty Behaviour of Turbulent Particle and Energy Fluxes in Edge Plasma of HT-7 Tokamak

High time resolution measurements of the electrostatic fluctuations and the turbulent particle and energy fluxes have been performed with a Langmuir probe array in the edge plasma in HT-7 tokamak. Bursty behaviour was observed in the time resolved turbulent fluxes with positive skewness and large kurtosis. The contribution of the large sporadic bursts to the transport losses were estimated. The analysis shows that the turbulent fluxes have different behaviour in different frequency domains and the probability distribution functions (PDFs) of the particle and energy fluxes present two distinct scaling ranges. All these are essentially consistent with the predictions of the self-organized criticality (SOC) model, though further studies are needed