Particle Confinement of Limiter- and Divertor-Dominated NBI Plasmas in CHS

Particle confinement time τ_p has been obtained from measurements of poloidal and toroidal distributions of Ha and Lyman a emissions in CHS. These particle confinement times range between 1.5 and 4ms at a constant line-averaged density of 3×10¹³cm^–3 for both cases of limiter- and divertor-dominated NBI plasmas with Ti-gettering. In these cases the energy confinement time τE were between 2 and 3ms. The density decay characteristic time τ_p* and global recycling coefficient R have been also measured for Ti-gettered plasmas and large τ_p* values were observed. As a result high recycling rates (R>0.92) are obtained for a wide density range. For a limiter-dominated case of boronized plasmas (R_ax=92.1cm) values of τ_p were correlated with τE and a linear correlation between them was found for normalized τE to P^-0.58 which is a power degradation term in LHD empirical scaling.