Transport of neutrals in turbulent Scrape-off-Layer plasmas

The effect of turbulence on the transport of neutral species (atom, molecules) in plasmas is investigated. A stochastic model relying on a multivariate gamma distribution is used to describe turbulent fluctuations. This model incorporates several important known features of Scrape-off-Layer turbulence, and has been implemented in the EIRENE Monte Carlo code. The effect of fluctuations on the neutral density, ionisation source and Balmer α radial profiles are investigated. Two important control parameters are identified, namely the ratio of the neutral mean free path to the size of turbulent structures, and the ratio of recycling time scales to the turbulent times.