Mechanisms of electric propulsion

Summary form only given, as follows.The technology of electric propulsion evolved to overcome the high propellant weight associated with propulsion by chemical means. As opposed to ejecting propellant at velocities of kilometers per second, exhaust velocities of plasma at tens of kilometers per second and more could be accomplished through electrical means. Although higher exhaust velocities require higher on-board power, the reduced propellant requirements facilitate a large variety of space transportation missions, such as orbitraising, station-keeping, or other propulsion missions requiring the conservation of propellant mass such as interplanetary flight. To produce thrust by the application of electric forces, plasma can be accelerated directly, or ions can be accelerated and then neutralized to form flowing neutral plasma. The different mechanisms of acceleration are embodied in such thrust devices as ion thrusters, Hall thrusters, magnetoplasmadynamic thrusters, or arcjets. In each method of electric propulsion, different technological limitations arise from basic plasma properties. This talk reviews the basic acceleration mechanisms at play in contemporary means of electric propulsion within the broader context of accelerating plasma by any means.