Numerical imaging of edge plasma characteristics in the high-recycling scrape-off layer of the KSTAR tokamak

Edge plasma characteristics of a high-recycling divertor operation regime of the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak are presented. The results were obtained by numerical simulation using a two-dimensional (2-D) two-fluid edge plasma transport code coupled with a 2-D Monte Carlo recycling neutral transport code. The simulations successfully display the two major characteristics of a scrapeoff layer in a high-recycling regime: a parallel temperature gradient and parallel pressure conservation. The results of the simulation can be utilized to provide guidelines for future operation of the KSTAR tokamak regarding the relation between upstream plasma properties and divertor operation regimes.