Transient Transport Experiments in the CDX-U Spherical Torus

Munsat, T. ; Efthimion, P.C. ; Jones, B. ; Kaita, R. ; Majeski, R. ; Stutman, D. ; Taylor, and G.

Princeton University. Plasma Physics Laboratory.

关键词: Cdx-U Spheromak;    70 Plasma Physics And Fusion Technology;    Modulation;    Sawtooth Oscillations;    Magnetic Islands;   

DOI  :  10.2172/786537
RP-ID  :  PPPL-3574
RP-ID  :  AC02-76CH03073
RP-ID  :  786537

美国|英语

来源: UNT Digital Library

【 摘 要 】

Electron transport has been measured in the Current Drive Experiment-Upgrade (CDX-U) using two separate perturbative techniques. Gas modulation at the plasma edge was used to introduce cold-pulses which propagate towards the plasma center, providing time-of-flight information leading to a determination of chi(subscript e) as a function of radius. Sawteeth at the q=1 radius (r/a {approx} 0.15) induced heat-pulses which propagated outward towards the plasma edge, providing a complementary time-of-flight based chi(subscript e) profile measurement. This work represents the first localized measurement of chi(subscript e) in a spherical torus. It is found that chi(subscript e) = 1-2 meters squared per second in the plasma core (r/a < 1/3), increasing by an order of magnitude or more outside of this region. Furthermore, the chi(subscript e) profile exhibits a sharp transition near r/a = 1/3. Spectral and profile analyses of the soft X-rays, scanning interferometer, and edge probe data show no evidence of a significant magnetic island causing the high chi(subscript e) region.