A compact phase-locked relativistic extended interactions oscillator with low seed injection power

A compact, efficient, low-injection-power, phase-locked, relativistic extended interaction oscillator (IL-REIO) is introduced in this paper. The incorporation of two cascaded modulated cavities after the input cavity facilitates the generation of a premodulated electron beam. This approach effectively reduces the injection ratio (ρ) to 1.13E-3, significantly lowering the required injection power. The structure of the traveling standing wave extended interaction output cavity is investigated to enhance the interaction efficiency and reduce the interaction distance. The PIC simulation results demonstrate that, operating at a frequency of 5.97 GHz, the IL-REIO attains a saturated output power of 156 MW with an electronic efficiency of 49.5%, given an electron beam voltage and current of 450 kV and 700 A, respectively. This scheme utilizes a focused magnetic field with a strength of merely 0.26 T, offering an effective solution for deploying permanent magnet packages or lightweight solenoidal magnetic fields.