Electron Beam Generation in Plasma-Filled Diodes

A study has been made of the response of low-density (∼ ${10}^{13}$ ${\mathrm{cm}}^{-3\mathrm{}}$) plasmas when subjected to the very high electric fields of relativistic-electron-beam-accelerator diodes. An anomalous resistive behavior has not been seen. Instead, sheath formation at the cathode and electron-beam generation across the sheath has been found. This has important applications to the design of diodes for future electron-beam machines.