CHAOTIC OSCILLATIONS ENHANCED BY MAGNETOSONIC WAVES IN PLASMA-FILLED TRAVELING-WAVE TUBES

A theory of plasma-filled traveling-wave tubes (TWTs) is developed in which the effect of magnetosonic waves excited in plasma by the operat ing wave is taken into account. These waves are excited by the pondero motive force caused by the radial inhomogeneity of the axial component of the electric field of the operating wave. In the simplest case con sidered in the paper, this effect leads to an additional reactive nonl inearity in the wave envelope equation. This leads to a shrinkage of t he region of stable oscillations in TWTs with the feedback causing the self-excitation; at the same time, the region of stochastic oscillati ons becomes larger. The radiation spectrum of stochastic oscillations in plasma-filled TWTs in which magnetosonic waves are excited is much wider and more continuous than the spectrum of stochastic oscillations in vacuum TWTs with the same feedback. (C) 1998 American Institute of Physics. [S1070-664X(98)01311-1].