Dissipative instabilities in beam-plasma systems

Abstract

It is known that all types of beam-plasma instabilities (Cherenkov, cyclotron, etc.) at a high level of dissipation turn into dissipative instability (DI). Until recently, only one type of DI was known in the beam-plasma interaction theory. Its maximal growth rate depends on the beam density n b and the collision frequency ν in the plasma as . However, recent studies have shown the existence of two new, previously unknown types of DI. Here, the new DI are briefly justified from the same viewpoint. This became possible due to the developed approach, which makes it possible to solve completely the classical problem of the development of an initial perturbation for various flow instabilities. The first new DI arises in the results of solving of the problem in systems with weak beam-plasma coupling. Its maximal growth rate is inversely proportional to frequency of collisions in plasma . The second new DI manifests itself in the results of the same problem in a magnetized plasma waveguide with an over-limiting e-beam. Its maximal growth rate is . Besides, the presented method of solving the classical problem deserves attention in itself as it is applicable to all instabilities caused by relative motion of plasma components (all types of beam-plasma instabilities, Buneman instability, etc.).