The stability of forced nonlinear longitudinal oscillations in isotropic plasma is investigated. It is demonstrated that at certain ratio between the parameters of the plasma and the external force there arise parametric-like instabilities, and both harmonics and subharmonic oscillations of the order of 1/3 become unstable. The growth rate of the unstable oscillations and conditions under which they occur are defined.
The authors are obliged to Prof. Dr. M. Dl-Nadi and Dr. T. El-Khalafawy for encouragement and support. They also wish to thank Mr. V. V. Mouchkin for his aid in preparation of this manuscript for publication.
On a leave from theAtomic Energy State Committee, U. S. S. R.