Correlations of ELM Frequency with Pedestal Plasma Properties

JET and TCV data for the correlations between ELM frequency and plasma characteristics are analyzed in the framework of classical Fokker-Planck approach. A general formula is obeyed in wide range of ELM sizes with varying coefficients corresponding to the main engineering parameters. The values of the coefficients differ from those in the solution of Fokker-Planck equation for diffusion revealing the impact of non-diffusive transport. Preliminary estimations for the impact of plasma recycling and impurities on the quasi equilibrium state of pedestal plasma during ELM discharges are made. They will be verified with PIC simulation of the transport of plasma in the SOL and its interactions with the plates of the divertor.