Performance improvement studies of axially partitioned dual band magnetically insulated line oscillator

Abstract

In magnetically insulated line oscillator (MILO)s, a proportion of device current is responsible for the self-generated magnetic field that aids electron flow confinement in the anode cathode gap, thereby suitable RF generation. The device currents should not be high due to its direct impact on device efficiency, and electron energy depositions at load can lead to anode plasma formation. Also, the lower currents can facilitate the device to operate at larger voltages and/or for longer operational times. In this article, couple of axially partitioned dual band MILOs (DBMILO) designs that operate at lower device currents in comparison with the existing axially partitioned DBMILOs in the literature is presented. For one design with the radius of the slow wave structure (SWS), i.e., RSWS = 40 mm, the injection of the DC electron beam parameters 505 kV and 49 kA, generated an output RF power of ∼5.8 GW oscillating at 3.71 and 10.16 GHz (S-and X- bands) concurrently with ∼23.8% conversion efficiency. However, the other design (RSWS = 40.6 mm) at beam voltage 505 kV and device current of 47 kA generated an output RF power of >3.85 GW oscillating at 3.5 and 10.5 GHz, concurrently, where the frequencies are harmonically related. Thus, the proposed designs yielded significant device current reduction to ∼47 and ∼49 kA from ∼56 kA (existed), respectively, thereby drop of 16% and 12.5% to its counter designs, respectively. Also, there is substantial reduction in the electron energy depositions, thus the occurrence of anode plasma formations. Moreover, the peak conversion efficiency is enhanced to 23.4% and 16.4%, from 12.8%.