The lifetime of existing Vacuum Arc Thrusters (VATs) is fundamentally limited by their ignition system, motivating the exploration of alternative approaches. This work presents a novel demonstration of a compact laser ignition system based on laser diodes. A pulsed laser driver was developed to generate adjustable pulses. Microsecond laser pulses were focused onto candidate ablation materials biased by a pulse-forming network (PFN), where laser-induced ablation initiated the arc discharge. Experiments demonstrated successful ignition with pyrolytic carbon and graphite. Pyrolytic carbon showed near-instantaneous plasma ignition, suggesting a very low ignition threshold, but poor repeatability as surface modification by the arc discharge prevented further ignitions. Graphite, in contrast, exhibited strong repeatability with example conditions of a 0.65 mm gap, 400 V PFN voltage, and 49 J/cm² over 500 µs at 455 nm. By introducing a nearby flow path, the initial seed arc was elongated and transferred to a secondary material, where the main discharge occurred. This effectively decouples the ignition process from the electrode erosion. These results mark a pivotal step toward the development of VATs fully reliant on laser ignition.     «

The lifetime of existing Vacuum Arc Thrusters (VATs) is fundamentally limited by their ignition system, motivating the exploration of alternative approaches. This work presents a novel demonstration of a compact laser ignition system based on laser diodes. A pulsed laser driver was developed to generate adjustable pulses. Microsecond laser pulses were focused onto candidate ablation materials biased by a pulse-forming network (PFN), where laser-induced ablation initiated the arc discharge. Exper...     »