Recent experimental progress in the TMX-U thermal barrier tandem mirror experiment

Conference · Fri Jun 22 00:00:00 EDT 1984

OSTI ID:6565929

Turner, W C; Allen, S L; Casper, T A; Clauser, J F; Coensgen, F H; Correll, D L; Cummins, W F; Damm, C C; Foote, J H; Goodman, R K

Recent experiments on the TMX-U thermal barrier device at LLNL have achieved the end plugging of axial ion losses up to a central cell density of n/sub c/ = 2 x 10/sup 12/ cm. During these tests, the axial potential profile characteristic of a thermal barrier has been measured experimentally, indicating an ion-confining potential greater than 1.5 kV and a potential depression of 0.45 kV in the barrier region. The average beta of hot electrons in the thermal barrier has been increased to 15% and appears limited only by classical scattering and ECRH pulse duration. Furthermore, deuterium ions in the central cell have been heated with ICRF to an average energy of 1.5 keV, with a heating efficiency of 40%. During strong end plugging, the axial ion confinement time reached 50 to 100 ms while the nonambipolar radial ion confinement time was 5 to 15 ms - independent of end plugging. Radial ion confinement time exceeding 100 ms has been attained on shots without end plugging. Plates, floated electrically on the end walls, have increased the radial ion confinement time by a factor of 1.8. Further improvement in the central cell density during end plugging can be expected by increasing the ICRF, improving the central cell vacuum conditions and beam heating efficiency, and increasing the radial extent of the potential control plates on the end walls.

• Research Organization: Lawrence Livermore National Lab., CA (USA); Sandia National Labs., Livermore, CA (USA); Johns Hopkins Univ., Baltimore, MD (USA); TRW, Inc., Redondo Beach, CA (USA); Maryland Univ., College Park (USA); California Univ., Livermore (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6565929
• Report Number(s): UCRL-90879; CONF-840616-21; ON: DE84015605
• Conference Information: International conference on plasma physics, Lausanne, Switzerland, 27 Jun 1984
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700104* -- Fusion Energy-- Plasma Research-- Plasma Kinetics-Experimental-- (-1987)
BETA RATIO
CONFINEMENT
DOCUMENT TYPES
ELECTRON TEMPERATURE
MAGNETIC MIRRORS
OPEN PLASMA DEVICES
PLASMA CONFINEMENT
PLUGGING
REVIEWS
TANDEM MIRRORS
THERMAL BARRIERS
THERMONUCLEAR DEVICES
TMX DEVICES