Numerical Simulations of Intermittent Transport in Scrape-Off Layer Plasmas

Two-dimensional fluid simulations of interchange turbulence for geometry and parameters relevant for the scrape-off layer of confined plasmas are presented. We observe bursty ejection of particles and heat from the bulk plasma in the form of blobs. These structures propagate far into the scrape-off layer where they are lost due to transport along open magnetic field lines. From single-point recordings it is shown that the blobs have asymmetric conditional wave forms and lead to positively skewed and flat probability distribution functions. The radial propagation velocity may reach one tenth of the sound speed. These results are in excellent agreement with recent experimental measurements.