Operational Regimes of the National Spherical Torus Experiment

Conference · Mon Jan 01 00:00:00 EST 2001

OSTI ID:1022032

Mueller, D. ^[1]; Peng, Yueng Kay Martin ^[2]

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1. Princeton Plasma Physics Laboratory (PPPL)
2. ORNL

The National Spherical Torus Experiment (NSTX) is a proof-of-principle experiment designed to study the physics of Spherical Torus (ST), i.e. low aspect-ratio toroidal, plasmas. Important issues for ST research are whether the high-{beta} stability and reduced transport theoretically predicted for this configuration can be realized experimentally. In NSTX, the commissioning of a digital real-time plasma control system, the provision of flexible heating systems and the application of wall conditioning techniques were instrumental in achieving routine operation with good confinement. NSTX has produced plasmas with R/a {approx} 0.85m/0.68m, A {approx} 1.25, I{sub p} {<=} 1.1 MA, B{sub T} = 0.3-0.45 T, {kappa} {<=} 2.2, {delta} {<=} 0.5, and with auxiliary heating by up to 4 MW of High Harmonic Fast Waves, and 5 MW of 80 keV D{sup 0} Neutral Beam Injection (NBI). The energy confinement time in plasmas heated by NBI has exceeded 100 ms and a toroidal beta, {beta}{sub T} = 2{mu}{sub 0}<p>/B{sub T0}, where B{sub T0} is the central vacuum toroidal magnetic field, up to 22% has been achieved. HHFW power of 2.3 MW has increased the electron temperature from an initial 0.4 keV to 0.9 keV both with and without producing a significant density rise in the plasma. The early application of both NBI and HHFW heating has slowed the penetration of the inductively produced plasma current, modifying the current profile and, thereby, the observed MHD stability.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1022032
• Resource Relation: Conference: 28th EPS Conference on Contr. Fusion and Plasma Phys., Funchal, Portugal, 20010618, 20010618
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ASPECT RATIO
AUXILIARY HEATING
BEAM INJECTION
COMMISSIONING
CONFIGURATION
CONFINEMENT
CONFINEMENT TIME
CONTROL SYSTEMS
DENSITY
ELECTRIC CURRENTS
ELECTRON TEMPERATURE
HARMONICS
HEATING
HEATING SYSTEMS
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MEETINGS
NSTX DEVICE
OPERATION
PLASMA
POWER
STABILITY
TRANSPORT