Development of ECR microwave discharge ion thruster

Abstract A 10-cm-diam. electron-cyclotron-resonance (ECR) microwave discharge ion thruster has been fabricated. This thruster produces a plasma by means of ECR heating. Ions in the plasma are extracted and accelerated by electrostatic grids. Performance tests of the thruster were carried out for several kinds of magnetic field configurations inside its discharge chamber and at different distances between Sm–Co magnets and the electrostatic grids. Preliminary estimations of ion production cost, propellant utilization efficiency, and beam divergence of the thruster were reported. Also a computer code to analyze ECR plasma behavior in the thruster was described. The test results and the computer code will be used to develop a larger system (larger than 20 cm diam.).