Fluctuation-induced flux at the plasma edge in toroidal devices

Fluctuation-induced fluxes have a bursty character. As a consequence, a significant part of the total particle flux is carried out by sporadic, large transport bursts. The local flux distribution function is consistent with a near-Gaussian character of the fluctuations. The radial dependence of the statistical properties of plasma fluctuations and induced fluxes have been investigated in the plasma boundary region of the TJ-I tokamak [I. García-Cortés et al., Phys. Fluids B 4, 4007 (1992)] and the TJ-IU torsatron [E. Ascasibar et al., in Plasma Physics and Controlled Fusion Research, Proceedings of the 15th Conference on Plasma Physics and Controlled Nuclear Fusion Research, Seville (International Atomic Energy Agency, Vienna, in press)]. There is a striking similarity between the statistical properties of turbulent transport in both devices.