Azimuthal velocity measurements of ion thruster by laser-induced fluorescence spectroscopy

2016 Fiscal Year Final Research Report

• Project/Area Number: 26820376
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Aerospace engineering
• Research Institution: Japan Aerospace EXploration Agency
• Principal Investigator: Tsukizaki Ryudo 国立研究開発法人宇宙航空研究開発機構, 宇宙科学研究所, 助教 (70720697)
• Research Collaborator: Yamamoto Yuta
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: イオンエンジン / プラズマ / レーザ誘起蛍光法 / マイクロ波

Outline of Final Research Achievements

This study reports the first ground study to measure the azimuthal velocities of an ion thruster that produces roll torque. Through the operation of ion thrusters in space, it has been confirmed that thrusters cause an unexpected roll torque about the ion beam axis. To reveal the physical mechanism that produces this torque, laser-induced fluorescence spectroscopy was applied to a microwave ion thruster. This technique can be used to measure the azimuthal velocity by estimating the Doppler shift of xenon ions. By deconvolving these spectra, the azimuthal velocities were successfully measured, which was accurately reproduced by the simulated velocity profile obtained using a model including the effects of the misalignment of the grids and the Lorentz force produced by the magnetic field of the discharge chamber. A roll torque of 0.5 μm about the thrust axis was calculated from the velocity profile; this prediction agrees well with the flight data for the spacecraft.

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