Chronicle of ion-current instabilities: old and new

For counter-streaming ion currents along a uniform magnetic field, a purely growing instability exists with a growth rate as high as 16 times the ion gyrofrequency. When the streaming ions are only 1 percent of the stationary ions, the growth rate is still 4 times the gyrofrequency, but the real part is near the lower hybrid frequency. These instabilities are in addition to the Drummond-Rosenbluth ion mode. Finite β effects increase the growth rate and can be important for β greater than 10-4. In all this, T/sub parallel,+/ = T/sub parallel,-/ and T/sub perpendicular to/ = 0. (U.S.)