Studies on Plasma Production and Ion Heating by Using Only a Single Helical Antenna for a Simple Thruster

Recently, studies of electric propulsion have been actively performed, and a new structure of radio frequency control has been proposed. The thrust of radio frequency driven electric propulsion is provided via plasma production and ion heating produced by excited wave of application of radio frequency. If the excited waves at the ion cyclotron resonance are left hand polarized, the waves couple to ions and ion heating takes place. On the other hand, the right hand polarized waves do not couple with ions and their energy goes to electrons via waveparticle interaction or direct acceleration. By employing a single helical antenna, the left hand polarized waves are launched toward one direction parallel to the magnetic field, and the right hand polarized waves are launched toward opposite direction simultaneously. Therefore plasma production and ion heating can be achieved by using only a single helical antenna. Basic experiments to examine the proposed structure have been performed, showing consistent results with expected scenario.