Design of a high power X-band magnicon amplifier

We present a design study for an X-band frequency-doubling magnicon amplifier driven by a 500 keV, 172 A beam from a field-emission diode. This study makes use of steady-state particle simulations employing the realistic fields of magnicon cavities connected by beam tunnels, and includes the effects of finite electron beam diameter. The simulations propagate an electron beam through a sequence of deflection cavities at 5.7 GHz, followed by an output cavity that operates at 11.4 GHz. The deflection cavities and the output cavity contain synchronously rotating TM modes. The deflection cavities progressively spin up the beam transverse momentum, until α≡v_⊥/v_z >1, where v_⊥ and v_z are the velocity components perpendicular and parallel to the axial magnetic field. The output cavity uses this synchronously gyrating beam to generate microwave radiation at twice the drive frequency. Self-consistency of the simulation is achieved by iteration until power balance exists in each cavity, and until the optimum RF phase in each cavity is determined. The final magnicon circuit should produce 20 to 50 MW at 11.4 GHz, depending on initial beam diameter, with a drive power of 1 kW at 5.7 GHz