The Concept of a Hybrid Pulsed Plasma Thruster for Small-Size Space Satellites

A concept of a hybrid plasma source to be used as a micro satellite thruster is proposed, where the propellant is a liquid gallium–indium alloy. The plasma source operates in two modes: 1) generation of laser ablation plasma and 2) generation of plasma in a laser-triggered, low-voltage vacuum-arc discharge. The cathode in the discharge cell of the source represents a stainless-steel capillary filled with the working liquid. The laser beam target is the working liquid meniscus. Without any voltage in the discharge gap, only laser-ablated plasma is generated. Upon application of even a relatively low voltage (<1 kV), the ablation initiates a high-current vacuum-arc discharge. In the experiments, the discharge current and voltage waveforms were recorded and so were the images of plasma glow obtained with a HSFC-Pro 4-channel high-speed camera. Regularities of current flow in the high-current vacuum-arc discharge, initiated by the cathode laser ablation, are investigated.