Transition to ELM-free Improved H-mode by Lithium Deposition on NSTX Graphite Divertor Surfaces

Mansfield, D. K. ; Kugel, H. W. ; Maingi, R. ; Bell, M. G. ; Bell, R. ; Kaita, R. ; Kallman, J. ; Kaye, S. ; LeBlanc, B. ; Mueller, D. ; Paul, S. ; Raman, R. ; Roquemore, L. ; Sabbagh, S. ; Schneider, H. ; Skinner, C. H. ; Soukhanovskii, V. ; Timberlake, J. ; J. Wilgen,, ; Zakharov, L.

Princeton University. Plasma Physics Laboratory.

关键词: Modifications;    70 Plasma Physics And Fusion Technology;    Divertors;    Deposition;    Confinement;   

RP-ID  :  PPPL-4407
RP-ID  :  DE-ACO2-09CH11466
RP-ID  :  953213

美国|英语

来源: UNT Digital Library

【 摘 要 】

Lithium evaporated onto plasma facing components in the NSTX lower divertor has made dramatic improvements in discharge performance. As lithium accumulated, plasmas previously exhibiting robust Type 1 ELMs gradually transformed into discharges with intermittent ELMs and finally into continuously evolving ELM-free discharges. During this sequence, other discharge parameters changed in a complicated manner. As the ELMs disappeared, energy confinement improved and remarkable changes in edge and scrape-off layer plasma properties were observed. These results demonstrate that active modification of plasma surface interactions can preempt large ELMs.