Papers

Peer-reviewed
Nov, 2020

Application of a microwave cathode to a 200-W Hall thruster with comparison to a hollow cathode

Acta Astronautica
  • Takato Morishita
  • ,
  • Ryudo Tsukizaki
  • ,
  • Naoji Yamamoto
  • ,
  • Kiyoshi Kinefuchi
  • ,
  • Kazutaka Nishiyama

Volume
176
Number
First page
413
Last page
423
Language
Publishing type
Research paper (scientific journal)
DOI
10.1016/j.actaastro.2020.06.049

A hollow cathode is an efficient electron source in the self-heating mode utilizing the discharge power. However, in sub-ampere currents, it needs keeper power to maintain the thermionic electron discharge, which could decrease the thrust efficiency. To address this problem, we propose using a microwave cathode, which is based on the flight model of a microwave ion thruster neutralizer cathode, as an alternative to a hollow cathode. First, we redesigned the magnetic field of a microwave cathode discharge chamber and tested it in the diode mode configuration. The electron emission current is doubled compared to the original performance. Next, we coupled the improved microwave cathode with a 200-W class Hall thruster and compared the characteristics and performance with a hollow cathode. We confirmed that the magnetic field polarity affects the ignition characteristics. We measured the thrust by an inverted thrust stand, the ion energy distribution functions by a retarding potential analyzer, and the beam profiles by an ion collector. The thrust and thrust efficiency are equivalent for both types of cathode. The specific impulse is 10% higher in the case of the microwave cathode. Since the potential difference between the microwave cathode and ground rapidly increased at currents above 600 mA, this could be taken to be the trade-off point against the hollow cathode.

Link information
DOI
https://doi.org/10.1016/j.actaastro.2020.06.049
Scopus
https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85087522294&origin=inward
Scopus Citedby
https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85087522294&origin=inward
ID information
  • DOI : 10.1016/j.actaastro.2020.06.049
  • ISSN : 0094-5765
  • SCOPUS ID : 85087522294

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