Performance Improvements in the Relativistic Magnetron: The Effect of DC Field Perturbations

The effect of using a shaped or transparent cathode to enhance key performance parameters in the Michigan magnetron, such as output power, power efficiency, and mode purity, was examined using a massively parallel electromagnetic particle-in-cell code improved concurrent electromagnetic particle-in-cell. In simulations, we saw a dramatic increase in the range of magnetic field and input voltage over which the magnetron functions, an increase in output power, an increase in efficiency, an elimination of mode competition, and immediate start-up for both the shaped and transparent cathodes relative to the standard cathode. These simulations also revealed that the mechanism that is responsible for the improved performance that accompanies the transparent cathode may not be RF-azimuthal-field penetration but rather perturbations in the "dc" field resulting from the design of the novel cathodes themselves.