Published online by Cambridge University Press: 13 March 2009
Stationary wave interactions are considered in a non-uniform plasma involving a cold electron beam propagating along the plasma density gradient. The character of the interactions is shown to depend on the beam-to-plasma energydensity ratio. The coupling of the beam space-charge waves and slow Langmuir waves gives rise to anomalous mode conversion and to the excitation of intensive fields near the resonance point. The regime of amplification is proved to be universal but is found to be sensitive to the boundary conditions.