ELM-induced plasma transport in the DIII-D SOL

High temporal and spatial resolution measurements in the boundary of the DIII-D tokamak show that edge localized modes (ELMs) are composed of fast bursts of hot, dense plasma lasting similar to 25 mu s each that travel radially starting at the separatrix at similar to 450 m/s and rotate in the scrape off layer (SOL), convecting particles and energy to the SOL and walls. The temperature and density in the ELM plasma initially correspond to those at the top of the density pedestal but decay with radius in the SOL. The temperature decay length (similar to 1.2-1.5 cm) is much shorter than the density decay length (similar to 3-8 cm), which in turn decreases with increasing pedestal density. The local particle and energy flux at the wall during the bursts are 10-50% (similar to 1-2 x 10(21) m(-2) s(-1)) and 1-2% (-20-30 kW/m(2)) respectively of the LCFS average fluxes, thus particles are transported radially much more efficiently that heat. (c) 2004 Elsevier B.V. All rights reserved.