Extended interaction oscillator driven by a pseudospark-sourced beam at 0.4 THz

The generation of high-power radiation in the terahertz frequency range is challenging. Conventional vacuum electron devices suffer the quick drop in the power level due to the limit of current density from the thermionic cathode. The pseudospark discharge is a low-pressure gas discharge in an axially symmetric structure. It is able to generate an electron beam with the advantage of high current density up to 104 A/cm2 and no need for an external guiding magnetic field. It attracted great interest in driving a THz interaction circuit to generate high-power radiation1. Following the numerical and experimental studies at 100 GHz and 200 GHz, an extended interaction oscillator operating at 0.35 THz was simulated and optimized2, To increase the electron beam interaction area, a sheet beam can be generated using a rectangular collimator. The particle-in-cell simulations showed that with a beam voltage of 34 kV, corresponding to a pseudospark discharge voltage of 42 kV, and a current density of 5.0×107 A/m2, it achieved an output power of 1.8 kW. The tolerance study showed that with a±5 μm tolerance, the maximum frequency shift was within 1% and the output power remained larger than 500 W.