Radio-frequency biasing of ion acceleration grids with different propellants

Li, Yifei; Tang, Huan; Cai, Guobiao; Fu, Chencong; Wang, Weizong

doi:10.1088/1361-6595/ac525b

Cited by 11 publications

(19 citation statements)

References 50 publications

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“…The measured IEDFs showed a multi-peak profile and the main peak almost disappears with a wide energy spread (100-800 eV) when the measured DC self-bias voltage is 300 V [18,19]. In addition, the influence of different propellants on the plasma beam in RF acceleration is investigated [29]. The experimental and simulation results are consistent with the trend of the average ion velocity with the RF voltage amplitude.…”

Section: Introductionsupporting

confidence: 66%

Experimental study of a neutralizer-free gridded ion thruster using radio-frequency self-bias effect

Yang

Guo²,

Bai³

et al. 2023

Plasma Sci. Technol.

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An experimental study on the quasi-neutral beam extracted by a neutralizer-free gridded ion thruster prototype was presented. The prototype was designed using an inductively coupled plasma (ICP) source terminated by a double-grid accelerator. The beam characteristics were compared when the accelerator was radio-frequency (RF) biased and direct-current (DC) biased. An RF power supply was applied to the screen grid via a blocking capacitor for the RF acceleration, and a DC power supply was directly connected to the screen grid for the DC acceleration. Argon was used as the propellant gas. Furthermore, the characteristics of the plasma beam, such as the floating potential, the spatial distribution of ion flux, and the ion energy distribution function (IEDF) were measured by a four-grid retarding field energy analyzer. The floating potential results showed that the beam space charge is compensated in the case of RF acceleration without a neutralizer, which is similar to the case of classical DC acceleration with a neutralizer. The ion flux of RF acceleration is 1.17 times higher than that of DC acceleration under the same DC component voltage between the double-grid. Moreover, there are significant differences in the beam IEDFs for RF and DC acceleration. The IEDF of RF acceleration has a widened and multi-peaked profile, and the main peak moves toward the high-energy region with increasing the DC self-bias voltage. In addition, by comparing the IEDFs with RF acceleration frequencies of 3.9 MHz and 7.8 MHz, it is found that the IEDF has a more centered main peak and a narrower energy spread at a higher frequency.

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Section: Introductionsupporting

confidence: 66%

Experimental study of a neutralizer-free gridded ion thruster using radio-frequency self-bias effect

Yang

Guo²,

Bai³

et al. 2023

Plasma Sci. Technol.

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“…In this section, we conduct experimental verification and the RF oscillation is detected in the RF ion thruster BHRIT-4, which has already been tested in our recent study of neutralizer-free extraction [43]. The BHRIT-4 has a beam extraction system, which is composed of a screen grid, an acceleration grid and a grid insulator.…”

Section: Experimental Verification Of Rf Oscillationmentioning

confidence: 99%

Kinetic simulations of low-pressure inductively coupled plasma: an implicit electromagnetic PIC/MCC model with the ADI-FDTD method

Fu,

Dong,

et al. 2024

J. Phys. D: Appl. Phys.

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Low-pressure inductively coupled plasma (ICP) is promising for space electric propulsion. For the first time, an implicit electromagnetic particle-in-cell Monte Carlo collision model based on the alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method is developed to investigate low-pressure xenon plasma characteristics of a miniature ICP source. The induced simulated electric field is well consistent with that calculated by the finite element method, indicating that this method can provide an accurate estimation of the electromagnetic field. The simulation time step used in the ADI-FDTD method is no longer restricted by the Courant–Friedrichs–Lewy constraints. Compared with the FDTD method, the ADI-FDTD method increases the size of the time step and significantly improves computational efficiency. The method is validated by comparing the simulated and measured electron density and plasma potential profile and reasonable agreement is reached. Therefore, the model is used to investigate the temporal and spatial distribution of plasma properties and the influence of the current amplitude of radio frequency (RF) coil, applied frequency of RF coil and neutral gas pressure on the plasma dynamics in the ionization chamber of a miniature gridded RF ion thruster. To explain the influence of the operating parameters, a concept called ‘the energy relaxation characteristics of electrons in response to the change of electric field’ is proposed and verified. The simulations also find that the oscillation frequency of plasma properties is twice the applied frequency of RF coil. The oscillation characteristics reveal the dynamic energy balance in the ICP. The experiment on the gridded RF ion thruster BHRIT-4 confirms the oscillation by measuring the plasma sheath potential.

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“…As an inert gas, krypton, which has smaller mass, smaller collision cross-sections and higher ionization potential compared to xenon, is much more abundant on Earth than xenon. Therefore, krypton has become one of the ideal alternative propellants to reduce the dependence on the expensive gases and has attracted extensive international attention [3,22,23]. Potrivitu et al systematically tested the low current hollow cathode with krypton and observed the mode transition under several operation conditions [22].…”

Section: Introductionmentioning

confidence: 99%

Plasma behavior of a low current orificed hollow cathode using krypton propellant for electric thruster applications

Liu

Wang

et al. 2023

J. Phys. D: Appl. Phys.

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As a fundamental component, hollow cathode has been widely used in electric thruster applications. Krypton has be-come one of the ideal alternative propellant for hollow cathode due to its economy thus it is vital to understand the basic physical process of the discharge of Krypton-fed hollow cathode. This study set out to establish a two-dimensional fluid model coupled with the equations for gas flow and heat transfer allowing to obtain the self-consistent description of the cathode discharge. The anomalous collision term based on the formulations of Sagdeev and Galeev is considered in this model. The model is validated by comparing the simulated and measured plasma characteristic parameters and reasonable agreement is reached. The findings show that the discharge of the Krypton-fed hollow cathode is character-ized by the lower plasma density, higher electron temperature, and higher spatial electric potential compared with that of Xenon-fed hollow cathode and tends to present a higher plasma density in the cathode plume region when it is operat-ing with the diode configuration. The double layer formed at the keeper orifice is an important factor for the low elec-tron temperature distribution which is greatly affected by the keeper current. These findings add to our understanding of plasma behavior in the discharge of a low current Krypton-fed hollow cathode and support further development of cred-ible Krypton-fed hollow cathode.

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Radio-frequency biasing of ion acceleration grids with different propellants

Cited by 11 publications

References 50 publications

Experimental study of a neutralizer-free gridded ion thruster using radio-frequency self-bias effect

Experimental study of a neutralizer-free gridded ion thruster using radio-frequency self-bias effect

Kinetic simulations of low-pressure inductively coupled plasma: an implicit electromagnetic PIC/MCC model with the ADI-FDTD method

Plasma behavior of a low current orificed hollow cathode using krypton propellant for electric thruster applications

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