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.

Under circumstances where parametric decay occurs in a plasma, a lower hybrid pump wave modulated near ion cyclotron harmonics is found to increase ion temperatures up to a factor of two over CW pump wave application. © 1985.