Electron Density Measurement Inside a Hall Thruster Using Microwave Interferometry

Kuwabara, Naoya; Chono, Masatoshi; Yamamoto, Naoji; Kuwahara, Daisuke

doi:10.2514/1.b38163

Cited by 5 publications

(1 citation statement)

References 19 publications

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“…Interferometry is a common diagnostic in plasma plumes, namely Hall thrusters, because of its non-invasive nature. Examples of this diagnostic include measurements made in Xenon [81][82][83][84][85], and Hydrogen [86]. A recent review on the applicability of this technique for atmospheric entry applications is provided in [26].…”

Section: Microwave Interferometery Specifications and Requirementsmentioning

confidence: 99%

VUV to IR Emission Spectroscopy and Interferometry Diagnostics for the European Shock Tube for High-Enthalpy Research

Ferreira

Carvalho

Alves

et al. 2023

Sensors

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The European Shock Tube for High-Enthalpy Research is a new state-of-the-art facility, tailored for the reproduction of spacecraft planetary entries in support of future European exploration missions, developed by an international consortium led by Instituto de Plasmas e Fusão Nuclear and funded by the European Space Agency. Deployed state-of-the-art diagnostics include vacuum-ultraviolet to ultraviolet, visible, and mid-infrared optical spectroscopy setups, and a microwave interferometry setup. This work examines the specifications and requirements for high-speed flow measurements, and discusses the design choices for the main diagnostics. The spectroscopy setup covers a spectral window between 120 and 5000 nm, and the microwave interferometer can measure electron densities up to 1.5 × 1020 electrons/m3. The main design drivers and technological choices derived from the requirements are discussed in detail herein.

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Section: Microwave Interferometery Specifications and Requirementsmentioning

confidence: 99%

VUV to IR Emission Spectroscopy and Interferometry Diagnostics for the European Shock Tube for High-Enthalpy Research

Ferreira

Carvalho

Alves

et al. 2023

Sensors

View full text Add to dashboard Cite

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Reflectometry diagnostics for atmospheric entry applications: state-of-the-art and new developments

et al. 2023

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Insight into the plasma properties of high-speed ionized flows is key for the validation of predictive aerothermodynamic tools for atmospheric entry applications, namely plasma radiation which will be highly dependent on the flow electron densities, which accordingly need to be accurately estimated. We performed an extensive review on past re-entry microwave diagnostics, including both in-flight and ground-test experiments. This work assesses the peculiar characteristics of entry plasmas, and derives functional requirements for microwave diagnostics tailored for such applications. A preliminary analysis, including a simulation of electromagnetic environment for the RAM-C II flight experiment, obtained through a CFD code coupled to an electromagnetic propagation code, is presented. The obtained results outline the adequacy of such diagnostics for improving verification and validation for high-speed entry plasma flows.

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Portable Thomson scattering system for temporally resolved plasma measurements under low density conditions

Yamamoto,

Yalin

2024

Review of Scientific Instruments

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We present the development of a portable Thomson scattering diagnostic system allowing simultaneous spatially and temporally resolved plasma property measurements for low density plasmas. The setup uses a compact pulsed Nd:YAG laser (532 nm) as the light source with suppression by two volume Bragg grating notch filters and dispersion with a single-stage spectrometer before measurement with an intensified camera. A key issue is the detailed light collection and how it impacts the sensitivity and elastic light suppression, for which we have investigated two optical configurations, one based on a 7 × 1 linear fiber bundle and the other based on a slit spatial-filter. We find that the configuration with the slit spatial-filter provides a higher sensitivity by a factor of ∼2 along with more uniform spatial response. We have developed a custom pulsed-plasma setup with a modulation at 20 kHz, representative of the Hall thruster breathing mode oscillation, to show the possibility of temporally resolved measurements for electric propulsion applications. We have successfully recorded the variations in electron number density and temperature with sub-mm spatial resolution and capturing ten temporal points over the 50 µs modulation period. The detection limit of electron density (with the spatial-filter configuration) is ∼1.6 × 1017 m−3, which is ∼1/10 of the plasma density in the acceleration channel of Hall thrusters.

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Electron Density Measurement Inside a Hall Thruster Using Microwave Interferometry

Cited by 5 publications

References 19 publications

VUV to IR Emission Spectroscopy and Interferometry Diagnostics for the European Shock Tube for High-Enthalpy Research

VUV to IR Emission Spectroscopy and Interferometry Diagnostics for the European Shock Tube for High-Enthalpy Research

Reflectometry diagnostics for atmospheric entry applications: state-of-the-art and new developments

Portable Thomson scattering system for temporally resolved plasma measurements under low density conditions

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