Abstract :
Summary form only given, as follows. The National Spherical Torus Experiment (NSTX) is designed to assess the potential of the low-aspect-ratio spherical torus concept for magnetic plasma confinement. NSTX has a plasma major radius of 0.85 m and minor radius of 0.68 m and has achieved plasma elongation of up to 2.5, plasma current (I/sub p/) up to 1.4 MA and toroidal field (B/sub T/) of 0.6 T. The plasma has been heated by up to 5 MW of neutral beam injection, NBI, at an injection energy of 90 keV and up to 6 MW of high harmonic fast wave, HHFW, at 30 MHz. An advantage of a spherical torus is that /spl beta/, the ratio of plasma pressure to magnetic pressure, can be higher in the spherical torus than in a normal aspect ratio tokamak. Some results of ongoing experiments on NSTX are reported.
Keywords :
Tokamak devices; ballooning instability; kink instability; plasma beam injection heating; plasma diagnostics; plasma magnetohydrodynamics; plasma toroidal confinement; sawtooth instability; tearing instability; 0.6 T; 1.4 MA; 5 MW; 90 keV; L-mode scaling; MHD phenomena; National Spherical Torus Experiment; Thomson scattering; ballooning modes; bootstrap current fraction; charge exchange spectroscopy; coaxial helicity injection; current driven kinks; efficient current drive mechanism; energy confinement times; large sawteeth; large toroidal rotation; locked modes; low-aspect-ratio spherical torus; magnetic plasma confinement; neoclassical tearing modes; neutral beam injection heating; power handling capability; reduced electron thermal transport; resistive wall modes; transitions to H-mode; Heating; Plasma confinement; Plasma density; Plasma measurements; Plasma simulation; Plasma stability; Plasma temperature; Plasma transport processes; Tellurium; Toroidal magnetic fields;
