Theory, simulation, and experimental results of the transvertron HPM source

Summary form only given. The transvertron oscillator or amplifier is a moderate impedance (50-100-Ω moderate voltage) (>400-kV) transit time oscillator (TTO). The frequency-transit time product of electron oscillations in the cavity determines the parameter regime over which the instability will grow or be damped. The distinction between the transvertron and other TTO sources is the reliance on forces perpendicular to the beam propagation direction. Analytical tools have been developed which help define the optimal operating regime for the source. In addition, long-pulse experiments which overcome the slow instability growth rate and low cavity noise have been conducted at L-band frequencies. The effect of the cavity length to radius ratio on growth rate and mode selection has been determined. The experimental results are in excellent agreement with theory and simulation. Clean microwave pulses with base widths of greater than 1 μs have been observed