Abstract
The main aim of the National Spherical Torus Experiment (NSTX) is to establish the fusion physics principles of the spherical torus (ST) concept. The NSTX device began plasma operations in February 1999 and the plasma current Ip was successfully brought up to the design value of 1 million amperes on December 14, 1999. The planned plasma shaping parameters, k = 1.6 - 2.2 and d = 0.2 - 0.4, were achieved in inner limited, single null and double null configurations. The CHI (Coaxial Helicity Injection) and HHFW (High Harmonic Fast Wave) experiments were also initiated. A CHI injected current of 27 kA produced up to 260 kA of toroidal current without using an ohmic solenoid. With an injection of 2.3 MW of HHFW power, using twelve antennas connected to six transmitters, electrons were heated from a central temperature of 400 eV to 900 eV at a central density of 3.5 x 1013 cm-3 increasing the plasma energy to 59 kJ and the toroidal beta, bT to 10 %. Finally, the NBI system commenced operation in Sept. 2000. The initial results with two ion sources (PNBI = 2.8 MW) shows good heating, producing a total plasma stored energy of 90 kJ corresponding to bT � 18 % at a plasm current of 1.1 MA.
