Dissipative instability under weak beam-plasma coupling in finite magnetic field

Beam-plasma interaction is considered in a model of plasma microwave generator: cylindrical waveguide with thin annular plasma and spatially separated thin annular e-beam. Finite external longitudinal magnetic field and dissipation are assumed. Such a configuration is favorable to trigger a new type of dissipative beam instability with more critical, as compared to conventional, inverse proportional dependence of the growth rate on the dissipation.