P-19 · Dissipative Instability of Overlimiting Electron Beam In No Uniform Cross-Section SystemRostomyan, Eduard1) Abstract Streaming instabilities are the most frequently encountered plasma instabilities e.g. well known beam-plasma instability. Their physics is elaborated and it may seem that one fail to encounter a variety of that with new physics. This investigation presents new type of beamplasma instability. It realizes under high beam current and in presence of high level of dissipation in no uniform cross-section system. Mechanisms of beam-plasma instability under very high beam current are of special interest. Traditional concepts of physical nature of beam-plasma instability are not applicable to such systems. In this case beam inner degrees of freedom and its space charge play an important role. The instability is due not to induced radiation of the system proper waves, but either to aperiodic modulation of the beam density in system with negative dielectric constant or to excitation of beam space charge wave with negative energy. The last variety of beam instability realizes in system, which are no uniform in cross-section. The threshold current is limiting vacuum current for given system.
|
Synopsis (pdf)