Simulation of flows within an electrostatic ion thruster for space missions

Ion thrusters are well suited for near-Earth and deep space missions becaus e of their exceptionally high specific impulse. Those already flying are al so proving to be very reliable. The flow of neutral and charged particles w ithin the different components of these devices is very complex and althoug h they have been studied for several years, little of the detail of their i nternal operation is properly understood. Numerical simulations of these fl ows can potentially yield an improved understanding of the physical phenome na involved and in turn this should assist in the optimising of new designs and in achieving higher specific impulses. The external plume, which can p otentially cause damage to other spacecraft components such as solar panels , has been the object of some studies ((1.2)) but the flow within the inter nal chambers where many complex phenomena are suspected to occur has been s eriously neglected. For this reason the present fully kinetic neutral and c harged particle simulations, which take account of the ionisation processes and the applied magnetic field, have been conducted. The studies have been made on one specific electrostatic ion thruster - the T5 model produced by the Space Department at the Defence and Evaluation Research Agency (DERA, Farnborough, UK)((3)). Two regions within the thruster have been concentrat ed on, namely the exit area of the hollow cathode and the main chamber.