Measurement of axial neutral density profiles in a microwave discharge ion thruster by laser absorption spectroscopy with optical fiber probes

Journal Article · Thu Dec 15 00:00:00 EST 2011 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.3665954· OSTI ID:22062376

Tsukizaki, Ryudo; Koizumi, Hiroyuki ^[1]; Nishiyama, Kazutaka; Kuninaka, Hitoshi ^[2]

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1. The University of Tokyo, Bunkyo-ku, Tokyo 113-8656 (Japan)
2. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Chuo-ku, Sagamihara, Kanagawa 229-8510 (Japan)

In order to reveal the physical processes taking place within the ''{mu}10'' microwave discharge ion thruster, internal plasma diagnosis is indispensable. However, the ability of metallic probes to access microwave plasmas biased at a high voltage is limited from the standpoints of the disturbance created in the electric field and electrical isolation. In this study, the axial density profiles of excited neutral xenon were successfully measured under ion beam acceleration by using a novel laser absorption spectroscopy system. The target of the measurement was metastable Xe I 5p{sup 5}({sup 2}P{sup 0}{sub 3/2})6s[{sup 3}/{sub 2}]{sup 0}{sub 2} which absorbed a wavelength of 823.16 nm. Signals from laser absorption spectroscopy that swept a single-mode optical fiber probe along the line of sight were differentiated and converted into axial number densities of the metastable neutral particles in the plasma source. These measurements revealed a 10{sup 18} m{sup -3} order of metastable neutral particles situated in the waveguide, which caused two different modes during the operation of the {mu}10 thruster. This paper reports a novel spectroscopic measurement system with axial resolution for microwave plasma sources utilizing optical fiber probes.

• OSTI ID: 22062376
• Journal Information: Review of Scientific Instruments, Vol. 82, Issue 12; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ABSORPTION SPECTROSCOPY
ACCELERATION
DENSITY
DISTURBANCES
ELECTRIC FIELDS
ELECTRIC POTENTIAL
EXCITED STATES
HIGH-FREQUENCY DISCHARGES
ION BEAMS
ION THRUSTERS
MICROWAVE RADIATION
NEUTRAL PARTICLES
OPTICAL FIBERS
PLASMA DIAGNOSTICS
PROBES
SPATIAL RESOLUTION
WAVEGUIDES
WAVELENGTHS