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Title: Physics results from the National Spherical Torus Experiment

Conference ·
OSTI ID:767420

The mission of the National Spherical Torus Experiment (NSTX) is to extend the understanding of toroidal physics to low aspect ratio (R/a {approx} 1.25) in low collisionality regimes. NSTX is designed to operate with up to 6 MW of High Harmonic Fast Wave (HHFW) heating and current drive, 5 MW of Neutral Beam Injection (NBI), and Co-Axial Helicity Injection (CHI) for non-inductive startup. Initial experiments focused on establishing conditions that will allow NSTX to achieve its aims of simultaneous high-{beta}{sub t} and high-bootstrap current fraction, and to develop methods for non-inductive operation, which will be necessary for Spherical Torus power plants. Ohmic discharges with plasma currents up to 1 MA, stored energies up to 55 kJ, {beta}{sub t} {approx} 10%, and a range of shapes and configurations were produced. Density limits in deuterium and helium reached 80% and 120% of the Greenwald limit respectively. Significant electron heating was observed with up to 2.3 MW of HHFW. Up to 270 kA of toroidal current for up to 200 msec was produced noninductively using CHI. Initial NBI experiments were carried out with up to two beam sources (3.2 MW). Plasmas with stored energies of up to 140 kJ and {beta}{sub t}=21% were produced.

Research Organization:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
US Department of Energy (US)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
767420
Report Number(s):
LA-UR-00-5365; TRN: US0100683
Resource Relation:
Conference: 42nd APS Division of Plasma Physics Meeting, Quebec (CA), 10/23/2000--10/27/2000; Other Information: PBD: 1 Nov 2000
Country of Publication:
United States
Language:
English