Application of divertor cryopumping to H-mode density control in DIII-D

In this paper we describe the method and the results of experiments where a unique in-vessel cryopump-baffle system was used to control density of H-mode plasmas. We were able to independently regulate current and density of ELMing H-mode plasmas, each over a range of factor two, end measure the H-mode confinement scaling with plasma density and current. With a modest pumping speed of /spl ap/40 kl/s, particle exhaust rates as high as 2/spl times/10/sup 22/ atom/s/sup -1/ have been observed.