Enhanced Electric Breakdown Strength in an Electron-Optical System

We describe the results of our work on enhanced electric breakdown strength observed in the plasma-anode bipolar optical system of a plasma-cathode electron gun. This kind of optical system uses a plasma-filled diode in which the acceleration and formation of the electron beam occurs in the double layer between the emission surface of the plasma cathode, stabilized by a fine-grained mesh, and the open surface of the anode plasma. The anode plasma is created by self-contained gas-discharge plasma sources whose original design was based on a plasma thruster with anode layer. The parameters of the plasma source are almost independent of the electron beam parameters, and its use in an electron gun enhances the breakdown strength of the acceleration gap and nearly doubles the electron beam current. The thruster-based plasma optical system (POS) resolves the anode grid problem and opens the way to controllable plasma-filled wide-aperture POS. We show that the POS can be effectively used for large-area electron beam formation.