This book is devoted to the non-linear theory of the collective interaction between a modulated beam of relativistic charged particles and narrow electromagnetic and Langmuir wave packets in plasma or gas slow-wave systems. Regular oscillations excited by a relativistic beam under the conditions of Cherenkov resonance and the anomalous Doppler effect can be used to generate coherent microwave radiation and accelerate charged particles in plasma.

Interaction between an electron beam and a fully ionized plasma has been studied with a view towards its application in a structure-less traveling wave tube. Three basic approaches, of varying degree of rigor, to the problem have been pursued and analytical solutions for the circularly symmetric case obtained. Comparisons between the methods of analysis are made. (Author).

Experimental results are presented for the heating of a 4 m long plasma confined by a uniform magnetic field of 4-5 kG by an intense relativistic electron beam. The initial plasma density ranged from approximately 5 x 10 to the 13th power cu cm to approximately 3 x 10 to the 15th power cu cm, the lower density cases being partially ionized and the higher density cases highly ionized. In all cases, the energy coupled from the beam to the plasma is greater than can be explained by binary collisions between beam electrons and the plasma particles. Over most of the density range tested, 5 x 10 to the 13th power cu cm to 1.5 x 10 to the 15th power cu cm the plasma heating cannot be explained by classical processes. These results are found to be explained quantitatively by the use of a full nonlinear treatment of the electron-electron two stream instability in the kinetic regime. A review of beam plasma interaction theory and previous experiments is presented to facilitate comparison with the present results.

An intense (5 x 105 Amp/cm2), relativistic (5 MeV), electron beam will be used to investigate the heating of small volumes (~5 to 10 cm3) of dense plasma (1017-- 1018 electrons/cm3) to kilovolt temperatures via the electrostatic two-stream instability.