Hall thruster ion acceleration neutralized by a radiofrequency inductively coupled plasma

A discharge in the annular cavity of a Hall effect thruster is sustained by extracting electrons from a radiofrequency (rf) inductively coupled plasma source located downstream of the thruster structure, where a radial magnetic field of 0.1-0.15 T is applied to the thruster discharge cavity by permanent magnets. Argon gas is introduced into the cavity via an anode structure and the ejected gas passes through the rf plasma source powered by a 13.56 MHz and 200 W generator. After turning on the rf plasma, a dc voltage is applied between a cathode installed inside the rf source and the anode of the Hall effect thruster, creating the bright annular discharge in the cavity. Measured ion energy distribution functions contain the energetic ions having the maximum potential close to the anode potential, demonstrating the ion acceleration from the annular cavity and the neutralization by the electrons in the rf plasma source.