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Effect of the hollow cathode Heat Power on the Performance of an Hall-Effect Thruster

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Plasma Science and Technology 2009年第2期11卷 194-199页

作者：宁中喜于达仁李鸿闫国军 HIT Plasma Propulsion Laboratory(HPPL) Harbin Institute of Technology

Effect of the hollow cathode heat power on the performance of a Hall-effect thruster is investigated. The variations in the Hall-effect thruster＇s performance （thrust, specific impulse and anode efficiency） with the hollow cathode heat power was obtained from the analysis of the experimental data. Through an analysis on the coupling relationship between the electrons emitted from the hollow cathode and the environmental plasma, it was found that the heat power would affect the electron emission of the emitter and the space potential of the coupling zone, which would lead to a change in the effective discharge voltage. The experimental data agree well with the results of calculation which can be used to explain the experimental phenomena.

关键词： hollow cathode Hall thruster plasma bridge

Coupling plasma plume of a low-power magnetically shielded Hall thruster with a hollow cathode

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Chinese Journal of Aeronautics 2020年第12期33卷 3018-3026页

作者： Guangchuan ZHANG Junxue REN Wei LIANG Ning OUYANG Chao LU Haibin TANG School of Space and Environment Beihang UniversityBeijing 100083China School of Astronautics Beihang UniversityBeijing 100083China Shanghai Institute of Space Propulsion Shanghai 201112China Key Laboratory of Spacecraft Design Optimization&Dynamic Simulation Technologies Ministry of EducationBeijing 100083China Laboratory of Space Environment Monitoring and Information Processing Ministry of Industry and Information TechnologyBeijing 100083China

The coupling region of a Hall thruster with a hollow cathode is the region between the cathode and the thruster plume.The characteristics of plasma in that region are complicated and strongly associated with the thruster working conditions and the cathode position.In this paper,a laboratory 100 W class magnetically shielded Hall thruster was coupled with a hollow cathode.Optical imaging and electrostatic probe were employed to monitor and scan the plasma plume.Plume characteristics in the coupling region in non-self-sustained mode and self-sustained mode were compared.Evolution of the coupling plume with the cathode position was studied.Experiments show that,when turning the thruster into self-sustained mode or moving the cathode further away axially,the discharge current can be reduced by 6.4–10.6%restraining the electron current and improving ionization.In particular,when the cathode is moved further,the electron conduction near the channel walls is suppressed.The electron current is reduced by 27.4%and the ion beam current is increased by 7%.Overall,this work shows that the working mode of the thruster and the position of the cathode greatly affect the coupling plasma plume.Both play an important role in improving the utilizations of propellant and current.

关键词： Coupling region Electron conduction Hall thruster hollow cathode Utilizations of propellant and current

Simulation of the spatio-temporal evolution of the electron energy distribution function in a pulsed hollow-cathode discharge

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Plasma Science and Technology 2023年第3期25卷 87-94页

作者： N A ASHURBEKOV K O IMINOV K M RABADANOV G S SHAKHSINOV M Z ZAKARYAEVA M B KURBANGADZHIEVA Dagestan State University Department of Physics Harbin Institute of Technology Institute of Physics Dagestan Federal Research CenterRussian Academy of Sciences

This article presents the 2D simulation results of a nanosecond pulsed hollow cathode discharge obtained through a combination of fluid and kinetic models.The spatio-temporal evolution of the electron energy distribution function(EEDF)of the plasma column and electrical characteristics of the nanosecond pulsed hollow cathode discharge at a gas pressure of 5 Torr are studied.The results show that the discharge development starts with the formation of an ionization front at the anode surface.The ionization front splits into two parts in the cathode cavity while propagating along its lateral surfaces.The ionization front formation leads to an increase in the fast isotropic EEDF component at its front,as well as in the anisotropic EEDF component.The accelerated electrons enter the cathode cavity,which significantly contributes to the formation of the highenergy EEDF component and EEDF anisotropy.

关键词： pulsed nanosecond discharge electron energy distribution fuinction hollow cathode electron kinetics gas discharge

Study of Discharging Characteristics of hollow cathode Surge Protective Gap

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Plasma Science and Technology 2010年第1期12卷 113-117页

作者：姚学玲陈景亮徐肖伟刘勇赵勇 State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical Engineering of Xi'an Jiaotong University

A hollow cathode surge protective gap （HCSPG） was designed, and the discharge characteristics was investigated in an air and nitrogen gas environment. For both the gap spacing D and the hole diameter Ф of HCSPG of 3 mm, the voltage protective value Up of HCSPG is about 3.5 kV and its converting time tc exceeds 100 ns at an air pressure from 10 Pa to 100 Pa. The maximum converting time tc from glow to arc discharging reaches 1600 ns at an air pressure of 100 Pa, while the minimum converting time tc is 120 ns at 10 Pa. For a triggered HCSPG, Up is reduced to about 1.6 kV while the converting time is 120 ns with a semiconductor trigger device and 50 ns with a dielectric porcelain trigger device under an air pressure of 100 Pa.

关键词： surge protective gap hollow cathode converting time trigger device

Uniformity of TiN Films Fabricated by hollow cathode Discharge

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Plasma Science and Technology 2010年第2期12卷 212-217页

作者：姜海富巩春志田修波杨士勤 R.K.Y.FU P.K.CHU State Key Lab.of Advanced Welding Production & Technology School of Material Science and Engineering Harbin Institute of Technology Department of Physics and Materials Science City University of Hong Kong

Titanium nitride （TIN） films were deposited on AISI 304 stainless steel substrates using hollow cathode plasma physical vapor deposition （HC-PVD）. Titanium was introduced by eroding the Ti cathode nozzle and TiN was formed in the presence of a nitrogen plasma excited by radio frequency （RF）. The substrate bias voltage was varied from 0 to -300 V and the uniformity in film thickness, surface roughness, crystal size, microhardness and wear resistance for the film with a diameter of 20 mm was evaluated. Although the central zone of the plasma had the highest ion density, the film thickness did not vary appreciably across the sample. The results from atomic force microscopy （AFM） revealed a low surface roughness dominated by an island-like morphology with a similar crystal size on the entire surface. Higher microhardness was measured at the central zone of the sample. The sample treated at -200 V had excellent tribological properties and uniformity.

关键词： hollow cathode TiN film uniformity

Impact of exterior electron emission on the self-sustaining margin of hollow cathode discharge

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Plasma Science and Technology 2020年第9期22卷 2-11页

作者：孟天航宁中喜于达仁 Harbin Institute of Technology Harbin 150001.People's Republic of China

hollow cathode researches used to focus on the inner cavity or downstream plume,however,rarely on the gap between the throttling orifice plate and the keeper plate(T-K gap),which was found to impact the self-sustaining margin of hollow cathode discharge in this paper.Near the lower margin,the main power deposition and electron emission and ionization regions would migrate from inner cavity and downstream plume to the T-K gap,in which case,the source and destination of each m A current therein matter for the self-sustaining capability.Changing the metal surfaces in the T-K gap with emissive materials proved effective in lowering the lower margin by supplementing auxiliary thermionic emission,compensating electron loss on cold absorbing walls and suppressing discharge oscillations.By doing so,the lower margin of a 4 A hollow cathode was lowered from 1 to 0.1-0.2 A,enabling it to couple with low power Hall thruster without extra keeper current.

关键词： hollow cathode self-sustained discharge secondary electron emission ionization oscillations thermionic emission

An experimental study on the degradation of the C12A7 hollow cathode

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Plasma Science and Technology 2022年第7期24卷 90-101页

作者：华志伟王平阳骆壮张忻田雷超 School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240People's Republic of China College of Materials Science and Engineering Beijing University of TechnologyKey Laboratory of Functional MaterialsBeijing 100124People's Republic of China Shanghai Institute of Space Propulsion Shanghai 201112People's Republic of China Shanghai Space Engine Engineering and Technology Research Center Shanghai 201112People's Republic of China

Emitter overheating is by far the greatest problem limiting the performance of novel C12A7 hollow cathodes. To explore the failure operating point and degradation mechanism of the C12A7 hollow cathode, microscopic analyses of a degraded electride emitter after 10 h of thermal electron emission are presented in this paper. The morphology and composition variation of overheated electride emitters by scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction indicate the melting and decomposition of electride of the surface layer. The monitored temperature of the electride emitter during the C12A7 hollow cathode operation shows that to avoid overheating the electride emitter, the average current density allowed should be about 64 m A mm^(-2) for the C12A7 hollow cathode in its current configuration. Experimental results of the heaterless C12A7 hollow cathode demonstrate that xenon(Xe) ion bombardment can remove the insulating layer and restore the thermionic emission capability for less degraded emitters. Based on experimental results and microscopic characterization, the depletion and degradation mechanisms of electride emitters during the hollow cathode operation are discussed.

关键词： C12A7 electride degradation micro characterization hollow cathode

Surface Charging Controlling of the Chinese Space Station with hollow cathode Plasma Contactor

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Plasma Science and Technology 2016年第7期18卷 727-731页

作者：蒋锴王先荣秦晓刚杨生胜杨威赵呈选陈益峰史亮汤道坦谢侃 Science and Technology on Vacuum Technology and Physics Laboratory Lanzhou Institute of Physics School of Aerospace Engineering Beijing Institute of Technology

A highly charged manned spacecraft threatens the life of an astronaut and extravehicular activity, which can be effectively reduced by controlling the spacecraft surface charging. In this article, the controlling of surface charging on Chinese Space Station （CSS） is investigated, and a method to reduce the negative potential to the CSS is the emission electron with a hollow cathode plasma eontactor. The analysis is obtained that the high voltage （HV） solar array of the CSS collecting electron current can reach 4.5 A, which can be eliminated by emitting an adequate electron current on the CSS. The theoretical analysis and experimental results are addressed, when the minimum xenon flow rate of the hollow cathode is 4.0 sccm, the emission electron current can neutralize the collected electron current, which ensures that the potential of the CSS can be controlled in a range of less than 21 V, satisfied with safety voltage. The results can provide a significant reference value to define a flow rate to the potential controlling programme for CSS.

关键词： active potential control hollow cathode space station plasma solar array

Study of hollow cathode Arc Welding Technology for Ti Alloys

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Journal of Materials Science & Technology 2001年第1期17卷 183-184页

作者： Zhihua LIU Qing ZHAO Deqing LI Aerospace Research institute of Materials&Processing Technology Beijing 100076China

In this paper, technology margin experiment of hollow cathode fusion arc welding (FAW) and penetrating arc welding (PAW) is presented in detail. The advantages of PAW. compared with FAW, are better weld formation, narrower welds, as well as a larger welding technology margin. Technological experiment and hydraulic test for the Ti alloy pressure vessels with PAW are described. Also, the weld formation control on Ti alloys is preliminarily analyzed. Finally, conclusions are addressed.

关键词： Welding Technology arc welding welding technology formation control pressure vessels hollow cathode Ti alloy