Experimental study of density pump-out on EAST

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.