Space Charge Effects in Dense, Velocity-Modulated Electron Beams

By assuming the bunching process of electrons in the drift region of a klystron as being space periodic, rather than time periodic, it is possible to describe the debunching mechanism in a finite diameter beam on a large signal basis. It is shown that such beams have a discrete spectrum of oscillations with the plasma frequency as series limits. This makes it impossible to assign a unique bunching parameter to all electrons. These results check with a velocity-phase analysis of high-density electron beams carried out with a beam analyzer at a frequency of 3000 Mc.