Experimental study of density pump-out on EAST**Supported by the National Magnetic Confinement Fusion Program of China (Nos.2012GB101002 and 2014GB106002), and National Nature Science Foundation of China (Nos.11375237 and 11105184).

Abstract

In the experimental advanced superconducting tokamak, density pump-out phenomena were observed by using a multi-channel polarimeter-interferometer system under different heating schemes of ion cyclotron resonant heating, electron cyclotron resonance heating, and neutral beam injection. The density pump-out was also induced with application of resonant magnetic perturbation, accompanied with a degradation of particle confinement. For the comparison analysis in all heating schemes, the typical plasma parameters are plasma current 400 kA, toroidal field 2 T, and line average density 2 × 1019 m−3. The experimental results show that the degree of pump-out is concerned with electron density and heating power. Low density deuterium low confinement (L-mode) plasmas (<3.5 × 1019 m−3) show strong pump-out effects. The density pump-out correlated with a significant drop of particle confinement.