Design of a High-Power W-band Rising-Sun Spatial Harmonic Magnetron for Fusion Power Generation

To provide high-power microwave for the heating and current drive (HCD) in the UK fusion power programme Spherical Tokamak for Energy Production (STEP), we have designed a W-band spatial harmonic magnetron (SHM) as a high-power millimeter wave source. The magnetron has 24 side cavities (rising-sun structure) and a novel axial output structure consisting of a funnel connected with a circular waveguide. Particle-in-cell (PIC) simulation results show that the magnetron could operate at $\pi$ mode and produce a high output power of 148 kW at 95 GHz, with an operation efficiency of 89.2%.