Recent activities in the development of the MOA thruster

Abstract

More than 60 years after the later Nobel laureate Hannes Alfvén had published a letter stating that oscillating magnetic fields can accelerate ionised matter via magneto-hydrodynamic interactions in a wave like fashion, the technical implementation of Alfvén waves for propulsive purposes has been proposed, patented and examined for the first time by a group of inventors.The name of the concept, utilising Alfvén waves to accelerate ionised matter for propulsive purposes, is MOA—magnetic field oscillating amplified thruster. Alfvén waves are generated by making use of two coils, one being permanently powered and serving also as magnetic nozzle, the other one being switched on and off in a cyclic way, deforming the field lines of the overall system. It is this deformation that generates Alfvén waves, which are in the next step used to transport and compress the propulsive medium, in theory leading to a propulsion system with a much higher performance than any other electric propulsion system.Based on computer simulations, which were conducted to get a first estimate on the performance of the system, MOA is a corrosion free and highly flexible propulsion system, whose performance parameters might easily be adapted in flight, by changing the mass flow and/or the power level. As such the system is capable to deliver a maximum specific impulse of 13116s (12.87mN) at a power level of 11.16kW, using Xe as propellant, but can also be attuned to provide a thrust of 236.5mN (2411s) at 6.15kW of power. First tests—that are further described in this paper—have been conducted successfully and underline the feasibility of the concept.While space propulsion is expected to be the prime application for MOA and is supported by numerous applications such as Solar and/or Nuclear Electric Propulsion or even as an “afterburner system” for nuclear thermal propulsion, other terrestrial applications can be thought of as well, making the system highly suited for a common space-terrestrial application research and utilisation strategy. This paper presents the recent developments of the MOA thruster R&D activities at QASAR, the company in Vienna, Austria, which has been set up to further develop and test the Alfvén wave technology and its applications.