Effect of heating scheme on SOL width in DIII-D and EAST

• DOI: 10.1016/j.nme.2017.01.024
• Publication Date: 2017-03-10T08:01:44Z
• Authors: L. Wang; M.A. Makowski; H.Y. Guo; A.W. Leonard; G.S. Xu; X.Z. Gong; A.M. Garofalo; G.Z. Deng; T.W. Petrie; D. Thomas; G. Jackson; G. Kramer; R. Maingi; J.B. Liu; W. Feng; H. Wang; B. Zhang; S. Ding; C.K. Pan; Y.J. Hu; J.P. Qian; J. Li; B.N. Wan
• Keywords: TK9001-9401; 0103 physical sciences; Nuclear engineering. Atomic power; 01 natural sciences; 7. Clean energy

Joint DIII-D/EAST experiments in the radio-frequency (RF) heated H-mode scheme with comparison to that of neutral beam (NB) heated H-mode scheme were carried out on DIII-D and EAST under similar conditions to examine the effect of heating scheme on scrape-off layer (SOL) width in H-mode plasmas for application to ITER. A dimensionally similar plasma equilibrium was used to match the EAST shape parameters. The divertor heat flux and SOL widths were measured with infra-red camera in DIII-D, while with divertor Langmuir probe array in EAST. It has been demonstrated on both DIII-D and EAST that RF-heated plasma has a broader SOL than NB-heated plasma when the edge electrons are effectively heated in low plasma current and low density regime with low edge collisionality. Detailed edge and pedestal profile analysis on DIII-D suggests that the low edge collisionality and ion orbit loss effect may account for the observed broadening. The joint experiment in DIII-D has also demonstrated the strong inverse dependence of SOL width on the plasma current in electron cyclotron heated (ECH) H-mode plasmas. Keywords: SOL width, Radio-frequency heating, Neutral beam heating, Low collisionality