Design and experimental results of a laser-ignited solid-propellant-fed magnetoplasmadynamic thruster.

A laser-ignited solid-propellant-fed magnetoplasmadynamic thruster (LISMPDT) is developed and tested. In this kind of thruster, a solid propellant is placed in a hollow cathode tube. When it works, the propellant is ablated and partially ionized by the laser; then, the plasma flow enters the chamber and is accelerated by the electromagnetic interaction. Unlike the typical magnetoplasmadynamic thrusters, almost any solid material can be used as a propellant in the LISMPDT; no tanks, valves, or piping systems are required for the propulsion system. Moreover, as the particles involved in the discharge process are produced from the laser ablation process, it would lead to a directed initial velocity and higher ionization. Meanwhile, a part of the energy serving the thruster could also be derived from the laser quasi as an add-on to the discharge energy with the separation of the ignition power and the ignition power unit from the thruster system. Experiments on the discharge characteristics and thrust performances were conducted and analyzed. The results validated the feasibility of the LISMPDT, and the maximal specific impulse reached ∼780 s, while the maximal thrust efficiency was expected to be about 9% under different operating conditions. It was also found that increasing the initial discharge voltage would effectively improve the propulsion performance while a longer laser pulse width led to reduced performance.