Beam Profile And Position Instability Of A Post-Accelerated Pseudospark-Sourced Electron Beam For An Extended Interaction Oscillator

摘要

The pseudospark discharge is a low-pressure gas discharge, that can generate extremely high currents within short rise times using a special hollow cathode structure. The highquality electron beam has high current density and brightness and the ability to self-focus via ion channel focusing. Simulations have shown the pseudospark-sourced electron beam can propagate within background plasma of density 10^{14-1016 m-3 with no applied guiding magnetic field, making it excellent for millimeter-wave generation. Single-shot electron beam pulses were imaged by a CCD camera measuring light emitted by electron beam impact on a 50 μm thickness stopping copper foil and phosphor screen. The high energy component beam profile has a Lorentzian distribution much smaller than the axial aperture size. A W-band (75-110 GHz) Extended Interaction Oscillator (EIO) millimeter-wave source was designed and constructed to operate in the 2π mode. With a 35 kV discharge voltage, the EIO successfully produced W-band radiation pulses of 200W peak power and 20ns pulse duration, agreeing with 3D Particle-in-Cell (PIC) MAGIC simulations. Simulations show the capability to extend this concept to higher frequencies.}