Recent Liquid Lithium Limiter Experiments in CDX-U

Majeski, R. ; Jardin, S. ; Kaita, R. ; Gray, T. ; Marfuta, P. ; Spaleta, J.

Technical Information Center Oak Ridge Tennessee

关键词: Liquid lithium limiters;    Carbon;    Electric currents;    Electron temperature;    First wall;   

RP-ID  :  DE2005839533

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports 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.