The relation between edge and divertor plasmas in the Large Helical Device

Abstract The relation between edge and helical divertor plasmas in the Large Helical Device are presented, in particular electron density ne and temperature Te behaviors, by line-averaged density n e scan ( n e ∼1–8×10 19 m−3) in the two typical magnetic configurations with relatively ‘thin’ and ‘thick’ naturally stochastic boundaries, respectively. The relations appear to be different in these configurations. With increasing n e , detachment-like behaviors of ne and Te are observed in the thick stochastic boundary configuration. On the other hand, both ne and Te at the divertor plate are almost proportional to them at near the last closed flux surface independent of n e . The different characteristics of particle screening and radiation power profile are suggested as causes of the different edge–divertor relations in these stochastic boundaries.