Particle and Energy Transport in the SOL of DIII-D and NSTX
POSTER
Abstract
While intermittent transport is the only SOL radial transport vehicle in L-mode, knowing the relative importance of inter-ELM vs ELM particle flux in H-mode is crucial. Density scans in DIII-D show that ELMs account for $\sim $90{\%} of the wall particle flux at low Greenwald fraction (f$_{g}\sim $0.4), decreasing to $\sim $30{\%} at f$_{g}\sim $1.0. Both intermittent transport and ELMs are comprised of filaments of hot, dense plasma (n$_{e}$ $\sim $ 1x10$^{13}$ cm$^{-3}$, T$_{e}\sim $100 eV) originating at the pedestal and convective in nature, leaving the pedestal region at speeds of $\sim $0.5-1 Km/s and losing heat and particles by parallel transport as they travel through the SOL. The intermittency and ELM heat is quickly lost, resulting in temperature radial decay lengths $\sim $1-2 cm, but the particles are not, resulting in radial density decay lengths $\sim $4-13 cm that increase inversely with SOL colissionality. In DIII-D the intermittency decays in both intensity and frequency in H-mode while it only decays in frequency in NSTX.
*Supported by the US DOE under DE-FG02-04ER54758, DE-AC02-76CH03073, DE-AC05-00OR22725, DE-AC04-94AL85000, and DE-FC02-04ER54698.