Microthruster based on a low voltage vacuum spark

Experimental studies of thrust characteristics of a small-size low voltage vacuum spark with liquid (InGa) cathode are present. It is shown that the view of the signal in the time-of-flight measurements depends strongly on the interelectrode gap, namely, the three ion components are present with the gap of 9 mm. The thrust of the plasma source depends on the interelectrode gap length and increase by 1.5 times with application of a permanent circular magnet. The thrust attains of P = 0.8 μNs with the stored energy of 0.1 J so that we may estimate the thrust to power ratio as 8 μNs/J as well as efficiency of the thruster η = PV/CU₀² ≈ 12% at U₀ = 250 V. Taking in mind the very small size, rather low mass that is about of 50 g, as well as the simple design of the source, we may conclude that it is a promising one as a thruster for the microsatellites.