Observation of nonlinear behavior of localized space-charge waves in space-charge dominated electron beams

We present an experimental observation of the abnormal growth of localized nonlinear fast space-charge waves in space-charge dominated electron beams passing through a dissipative channel. High-perveance electron beams with localized perturbations are launched from a gridded electron gun and transported through a short resistive-wall channel consisting of a resistive-film coated glass tube inside a long solenoid providing uniform focusing. The energy width of the space-charge waves developed from the perturbations is measured on both ends of the channel. The experiments have shown that the localized fast space-charge wave appears to grow under nonlinear perturbations; in the linear regime, as expected, the energy width of slow waves increases, while the energy width of fast waves decreases when they pass through the resistive channel