Water and xenon ECR ion thruster—comparison in global model and experiment

Nakagawa, Yuichi; Koizumi, Hiroyuki; Naito, Yoshiro; Komurasaki, Kimiya

doi:10.1088/1361-6595/aba2ac

Cited by 16 publications

(4 citation statements)

References 75 publications

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“…In the case of water vapor, on the other hand, the actual ion species and their abundance ratios in the plume have not been known. Instead, in reference to the previous research for a microwave discharge ion source [44], it was reported that OH + , H 3 O + , and O + were mainly observed other than H 2 O + , and their existence were 15 %, 12 %, and 5 % of H 2 O + , respectively. The referenced results, however, are assumed to be derived from different plasma parameters from those of the Hall thruster discharge plasma.…”

Section: Performance Analysis Methodsmentioning

confidence: 88%

Demonstration and experimental characteristics of a water-vapor Hall thruster

et al. 2023

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Water is an attractive candidate for condensable propellants owing to its availability, handleability, and sustainability. This study proposes the use of water vapor as a propellant for a low-power Hall thruster, and experimentally demonstrates the feasibility of this proposal. Based on the performance estimation from the plume diagnostics, a thrust-to-power ratio of 19 mN/kW, specific impulse of 550–860 s, and anode efficiency of 5–8 % were obtained at an anode power of 233–358 W. From further efficiency analysis, the mass utilization efficiency of water was found to be the most deteriorated among the internal efficiencies compared to the conventional xenon propellant, which was consistent with the expectations from a small discharge current oscillation, large beam divergence, and increase in low-energy ions. Moreover, additional power loss via reactions unique to polyatomic molecules was indicated by evaluation of the ionization cost. In this experiment, the mass utilization efficiency was improved with an increase in the anode voltage from 200 to 240 V without degradation of the power utilization. This suggests that operating at a higher voltage is more suitable for a water-vapor Hall thruster.

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Section: Performance Analysis Methodsmentioning

confidence: 88%

Demonstration and experimental characteristics of a water-vapor Hall thruster

et al. 2023

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“…In addition, integrating the discharge model [57] and the plume morphology model [58] into the model system can further improve the approximation introduced in equation ( 5). The NNM can be updated dynamically based on in-orbit test data using transfer-learning methods [59].…”

Section: Resultsmentioning

confidence: 99%

A neural network model relating extraction current characteristics with optical emission spectra for the purpose of a digital twin of miniaturized ion thrusters

Zhang¹,

Zhu²,

Wang³

et al. 2022

J. Phys. D: Appl. Phys.

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Miniaturized ion thrusters are one of the most important candidates in the task of drag-free control for space-based gravitational wave detection, whose thrust can be accurately tuned in principle by in-orbit monitoring and feedback controlling. This work investigates a neural network model (NNM) which can be used for real-time monitoring of the function relating the grid voltage and the extraction current of a miniaturized ion thruster by optical emission spectroscopy. This model is developed as a component of an ion thruster’s digital twin. A collisional-radiative model relates the plasma parameters in the discharge chamber of the thruster to the emission spectroscopy; an extraction current model relates the plasma parameters to the function relating grid voltage and extraction current. The neural network model is trained based on the dataset produced by these models, and is examined by experimental results from a miniaturized ion thruster. It is found that the difference between the thrust predicted by the NNM and the experimental value is less than 6%. Discussions are given on further improvement of the NNM for accurate thrust control in space-based gravitational wave detection in the future.

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“…Examples include the Beihangkongshi-1 satellite with NPT30-I2 that was injected into a circular, Sun-synchronous orbit [1], the European Space Agency's (ESA) BepiColombo mission to Mercury with the T6 Kaufmann-type thruster [2][3][4], the satellite SJ-9 A with the LIPS-200 ion thruster which carried out an ion electric propulsion system flight test plan [5,6], the gravity field and steady-state ocean circulation explorer (GOCE) mission using the T5 Kaufmann type thruster for drag compensation [7], the Dawn mission and the Deep Space 1 mission with the NASA Solar Technology Application Readiness (NSTAR) ion thruster of the National Aeronautics and Space Administration [8][9][10], the Japanese Aerospace Exploration Agency's Hayabusa sample-return missions with the µ10 thruster to the near-Earth asteroids [11], [12]. Meanwhile, the working mechanism of the ion thruster has also been extensively studied, including the discharge chamber [13][14][15][16] that generates plasma and the optic system [17][18][19][20][21][22] that provides thrust.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional analysis of RF-biased ion optics with misalignments of apertures

Wang

Liu

et al. 2023

Plasma Sources Sci. Technol.

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The accelerator grid holes shift is a critical reason for erosion failure of optic systems in ion thrusters, which may also cause an unexpected roll torque about the ion beam axis. A three-dimensional model of ion optics is developed based on particle-in-cell Monte Carlo collision (PIC-MCC) method to investigate the plasma dynamics and performance of the radio frequency (RF) grid systems with misalignments of apertures, which are compared with those in the direct current (DC) grid system. For benchmark case, the three-dimensional model gives a better agreement with the experiments in the ion energy distribution function (IEDF) compared with the two-dimensional model from a previous publication, with 36.4% and 47.9% relative error reduction of the peak position and full width at half maximum (FWHM) respectively, indicating the effectiveness of the developed three-dimensional model. Simulations show that in the RF grid system the ion beamlet is deflected in the direction opposite to the shift of the accelerator grid hole, while electrons move first in the holes shift direction, and then deflect in the opposite direction. The average ion beamlet deflection angle calculated is consistent with the predictions by the linear optical theory in both the RF and DC grid system. The amplitude of beamlet deflection angle fluctuation with time decreases with the increase of RF frequency. When the grid holes shift, the ion beamlet will deflect with the divergence angle almost unchanged in the DC grid system, while the beamlet divergence angle increases in the RF grid system. When RF frequency is low, the big vortex-like structure in electron velocity phase diagram breaks into small vortices, showing a reduced oscillation intensity. The holes shift also causes high-frequency oscillation in the shift direction. In terms of performance, RF grid system is more sensitive to grid holes shift than DC grid system.

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Water and xenon ECR ion thruster—comparison in global model and experiment

Cited by 16 publications

References 75 publications

Demonstration and experimental characteristics of a water-vapor Hall thruster

Demonstration and experimental characteristics of a water-vapor Hall thruster

A neural network model relating extraction current characteristics with optical emission spectra for the purpose of a digital twin of miniaturized ion thrusters

Three-dimensional analysis of RF-biased ion optics with misalignments of apertures

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