A NONLINEAR STUDY OF BEAM PLASMA AMPLIFICATION.
CALIFORNIA INST OF TECH PASADENA
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The interaction between an electron beam and the plasma oscillations it excites in traversing a plasma effectively changes the magnitude and direction of the force between beam electrons. The beam behavior is studied theoretically by computing in an exact, nonlinear manner, the trajectories of a disc model electron beam which traverses a linear, dielectric model plasma. The parameters varied are the beam space charge conditions beam current, the degree of initial velocity modulation, and the ratio of modulation frequency to plasma frequency. Computations show that iit is possible to bunch the beam electrons to within 85 of delta function bunching under some beam and plasma conditions. The electron beam behavior is studied experimentally by observing the beam electron velocity phase distribution with a crossed-field velocity analyzer, and observing the beam current waveform density-phase distribution using a wide-band sampling oscilloscope. Experimental results show essentially the same beam behavior as predicted by the computations with some differences which are attributed to variation in the plasma density along the beam path. Author
- Plasma Physics and Magnetohydrodynamics