Design of a Lightweight Confined-Flow Periodic Reversing Permanent Magnetic Field Based on E-Shaped Waveguide Relativistic Extended Interaction Oscillator

In this article, the design of a lightweight confined-flow periodic reversing permanent magnetic (CF-PRPM) field, integrated with an E-shaped waveguide relativistic extended interaction oscillator (ESW-REIO), is proposed. The research thoroughly investigates the transmission characteristics of the annular intensive relativistic electron beam (IREB) under the CF-PRPM field, using the Mathieu equation and Busch theorem as theoretical foundations. The structure of an ESW-REIO is used as a basis for the design and optimization of the CF-PRPM field. Employing a 450-kV, 700-A electron beam, particle-in-cell (PIC) simulations indicate that the ESW-REIO ultimately obtained an output power of 109.5 MW at 5.63 GHz, achieving a peak efficiency of 34.8% under the CF-PRPM field. One of the primary benefits of this design is its lightweight construction. Specifically, the weight of the permanent magnets and their packages in the CF-PRPM field are 1.1 and 0.65 kg, respectively, resulting in a total weight of only 3.3 kg for the ESW-REIO loaded with the CF-PRPM field. This yields a power-to-weight ratio of 33 MW/kg, which is a more acceptable figure for such a high-power device and illustrates the practicality and potential for miniaturization of the design.