Steady-state electron currents were driven by fast waves with cice in an initially current-free plasma in the Irvine Torus. Current direction was controlled by the fast-wave phased-array antenna. Low power experiments (<25 W) generated up to 1.3 A of electron current with a peak effeciency of =InR/P(6×10-2 A/W)(1013 cm-3)m. Up to 14% of the wave energy was converted to poloidal magnetic field energy. © 1986 The American Physical Society.

Fast waves with frequencies near the mean gyrofrequency [̂Ä(cice)12] were excited in a toroidal, magnetized plasma. Experimental measurements were made of wavelengths and phase velocities perpendicular to the toroidal magnetic field, and wave energy trajectories in the plasma, with varying wave frequency, plasma density, and magnetic field values. Experimental results agree with predictions from the cold-plasma dispersion relation. © 1986 The American Physical Society.

The development of a highly unidirectional lower-hybrid wave source would improve the electron current drive efficiency in tokamaks. Lower-hybrid waves launched from a phased wave array are shown to be reflected from a grid placed in a cold, low-density plasma. The antenna-grid combination results in highly unidirectional lower-hybrid waves. © 1985 American Institute of Physics.

A simple, gas-fed, radio-frequency-driven plasma source is described. By use of lower hybrid waves, noble gas plasmas were produced with electron densities up to 1012 cm-3 over a range of magnetic fields from 400 G to 1.5 kG and rf frequencies from 2-220 MHz.