Enhanced thrust from a plasma thruster due to collisions with neutrals

We have recently shown, in experiments conducted in our Radial Plasma Source (RPS), that the thrust per power from a plasma thruster can be increased due to ion-neutral collisions [1, 2]. The plasma in the RPS flows across a magnetic field so that the magnetic field pressure is the source of the thrust. We investigate the mechanism of thrust enhancement by studying how the mass flow rate and the magnetic field intensity affect the thrust. We relate the ion acceleration to the radial profile of the electric potential in the thruster. The plasma potential is deduced from measurements by emissive probe, which are interpreted by our recent theory for such a probe, for the regime that the probe radius is comparable to the plasma Debye length [3]. Most recently we have extended the experiments to include not only argon but also helium. In our recent experiments we explore how the way the gas is fed affects the delivered thrust, with the aim of exploring an air breathing scheme for propulsion.