Recent Liquid Lithium Limiter Experiments in CDX-U

Majeski, R. ; Jardin, S. ; Kaita, R. ; Gray, T. ; Marfuta, P. ; Spaleta, J. ; Timberlake, J. ; Zakharov, L. ; Antar, G. ; Doerner, R. ; Luckhardt, S. ; Seraydarian, R. ; Soukhanovskii, V. ; Maingi, R. ; Finkenthal, M. ; Stutman, D. ; Rodgers, D. ; Angelini, S.

Princeton University. Plasma Physics Laboratory.

关键词: Liquid Metals;    Oxygen;    70 Plasma Physics And Fusion Technology;    Edge Plasma;    First Wall;   

DOI  :  10.2172/839533
RP-ID  :  PPPL-4068
RP-ID  :  AC02-76CH03073
RP-ID  :  839533

美国|英语

来源: UNT Digital Library

【 摘 要 】

Recent experiments in the Current Drive eXperiment-Upgrade (CDX-U) provide a first-ever test of large area liquid lithium surfaces as a tokamak first wall, to gain engineering experience with a liquid metal first wall, and to investigate whether very low recycling plasma regimes can be accessed with lithium walls. The CDX-U is a compact (R=34 cm, a=22 cm, B{sub toroidal} = 2 kG, I{sub P} =100 kA, T{sub e}(0) {approx} 100 eV, n{sub e}(0) {approx} 5 x 10{sup 19} m{sup -3}) spherical torus at the Princeton Plasma Physics Laboratory. A toroidal liquid lithium pool limiter with an area of 2000 cm{sup 2} (half the total plasma limiting surface) has been installed in CDX-U. Tokamak discharges which used the liquid lithium pool limiter required a fourfold lower loop voltage to sustain the plasma current, and a factor of 5-8 increase in gas fueling to achieve a comparable density, indicating that recycling is strongly reduced. Modeling of the discharges demonstrated that the lithium limited discharges are consistent with Z{sub effective} < 1.2 (compared to 2.4 for the pre-lithium discharges), a broadened current channel, and a 25% increase in the core electron temperature. Spectroscopic measurements indicate that edge oxygen and carbon radiation are strongly reduced.