Simulation of discharge process of Hall thruster under the internal and external cathode conditions

Hall thruster has been used widely in orbit correction and station-keeping of geostationary satellites for the advantage of high specific impulse, long life, and high reliability. The cathode is an important part of Hall thruster, which can neutralize ion beam and provide electrons to the thruster for ionization. At present, the position of cathode can be divided into two kinds: internal cathode and external cathode. And the discharge parameters under the two different cathode positions is very different, such as the coupling voltage and the ion density. And this paper considers the mechanism of influence of the cathode position on the discharge process of Hall thruster, the discharge process of Hall thruster under internal and external cathode conditions was simulated by PIC-MCC simulation method. The simulation results show that the electron conduction near the thruster outlet is relatively strong under the internal cathode condition. The trajectory of electrons emitted from the cathode position under the two conditions is further simulated. The simulation results show that the electrons will be bound by the magnetic field and form a virtual cathode when they enter the simulation area. The lower coupling voltage under the internal cathode condition is explained by comparing the positions of virtual cathode. At the same time, some electrons emitted from the internal cathode position can quickly reach the main beam region. The ion density distribution is also compared. The ionization regions of Xe+, Xe2+ and Xe3+ ions are relatively outside under the internal cathode condition, and the peak densities of Xe2+ and Xe3+ ions are relatively low. Compared with the experimental results, it is shown that the electron trajectory in the plume region has a significant effect on the plume shape.

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Three-dimensional tomographically reconstructed optical emission profiles of Hall thruster plasmas

Plasma Sources Science and Technology ◽

10.1088/1361-6595/ac43c3 ◽

2021 ◽

Author(s):

jinwoo kim ◽

Dongho Lee ◽

Guentae Doh ◽

Sanghoo Park ◽

Holak Kim ◽

...

Keyword(s):

Radiative Decay ◽

Tomographic Reconstruction ◽

Gaussian White Noise ◽

Three Dimensional ◽

Diagnostic System ◽

Optical Emission ◽

Ccd Camera ◽

Hall Thruster ◽

Plume Region ◽

Reconstruction Performance

Abstract A diagnostic system was developed for spectrally resolved, three-dimensional tomographic reconstruction of Hall thruster plasmas, and local intensity profiles of Xe I and Xe II emissions were reconstructed. In this diagnostic system, 28 virtual cameras were generated using a single, fixed charge-coupled device (CCD) camera by rotating the Hall thruster to form a sufficient number of lines of sight. The Phillips-Tikhonov regularization algorithm was used to reconstruct local emission profiles from the line-integrated emission signals. The reconstruction performance was evaluated using both azimuthally symmetric and asymmetric synthetic phantom images including 5% Gaussian white noise, which resulted in a root-mean-square error of the reconstruction within an order of 10-3 even for a 1% difference in the azimuthal intensity distribution. Using the developed system, three-dimensional local profiles of Xe II emission (541.9 nm) from radiative decay of the excited state 5p4(3P2)6p2[3]˚5/2 and Xe I emission (881.9 nm) from 5p5(2P˚3/2)6p2[5/2]3 were obtained, and two different shapes were found depending on the wavelength and the distance from the thruster exit plane. In particular, a stretched central jet structure was distinctively observed in the Xe II emission profile beyond 10 mm from the thruster exit, while gradual broadening was found in the Xe I emission. Approximately 10% azimuthal nonuniformities were observed in the local Xe I and Xe II intensity profiles in the near-plume region (< 10 mm), which could not be quantitatively distinguished by analysis of the frontal photographic image. Three-dimensional Xe I and Xe II intensity profiles were also obtained in the plume region, and the differences in the structures of both emissions were visually confirmed.

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Comparison Between Experimental and Simulation Results for Ion Beam and Neutron Irradiations in Silicon Bipolar Junction Transistors

IEEE Transactions on Nuclear Science ◽

10.1109/tns.2008.2007561 ◽

2008 ◽

Vol 55 (6) ◽

pp. 3055-3059 ◽

Cited By ~ 5

Author(s):

E. Bielejec ◽

G. Vizkelethy ◽

R. M. Fleming ◽

W. R. Wampler ◽

S. M. Myers ◽

...

Keyword(s):

Ion Beam ◽

Bipolar Junction Transistors ◽

Simulation Results

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Feature Extraction Accuracy Improvement of Acoustic Signals Based on Reassigned Wavelet Scalogram

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.55-57.2065 ◽

2011 ◽

Vol 55-57 ◽

pp. 2065-2068

Author(s):

Pan Li ◽

Ping He ◽

Hui Qi Sun ◽

Wei Shang ◽

Nan Xiang Sun

Keyword(s):

Feature Extraction ◽

High Reliability ◽

Acoustic Signals ◽

Morlet Wavelet ◽

Frequency Error ◽

Accuracy Improvement ◽

Characteristic Frequencies ◽

Location Method ◽

Simulation Results ◽

Morlet Wavelet Transform

Based on the wavelet scalogram obtained by Morlet wavelet transform and hard threshold de-noising filtering for typical acoustic emission signals, region segmented location method is introduced to get the number and accurate values of the characteristic frequencies, therefore the error induced by misjudgment and misreading can be avoided effectively. Then considering the weakness of large characteristic frequency error in Morlet wavelet scalogram, the feature extraction accuracy has been improved by combing region segmented location method and reassigned wavelet scalogram. Simulation results show that the proposed method has the merits of well rapidity, high reliability and briefness, hence can realize high precision feature extraction and has great practical value.

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Alpha Radioactivity Monitor Using Ionized Air Transport Technology for Large Size Uranium Waste: Part 2—Simulation Model Reinforcement for Practical Apparatus Design

ASME 2010 13th International Conference on Environmental Remediation and Radioactive Waste Management, Volume 1 ◽

10.1115/icem2010-40091 ◽

2010 ◽

Author(s):

Takatoshi Asada ◽

Yosuke Hirata ◽

Susumu Naito ◽

Mikio Izumi ◽

Yukio Yoshimura

Keyword(s):

Ion Transport ◽

Simulation Model ◽

Cfd Simulation ◽

Transport Model ◽

Model Simulation ◽

Ion Density ◽

Transport Simulation ◽

Simulation Results ◽

Alpha Radioactivity ◽

Ionized Air

In alpha radioactivity measurement using ionized air transportation (AMAT), conversion from ion currents to radioactivity accurate is required. An ion transport simulation provides ways of complementarily determining conversion factors. We have developed an ion transport simulation model. Simulation results were compared with experiments with air speeds, faster than 1 m/s, achieving good agreement. In a practical AMAT apparatus, the air-flow at the alpha source may be slower than 1 m/s, and ion loss is likely to be large. Reinforcement of the ion transport model to cover the lower air speed region is effective. Ions are generated by an alpha particle in a very thin column. Since the ion density at this temporal stage is high, the recombination loss, proportional to the square of ion density, is dominant within a few milli-seconds. The spatial and temporal scales of this columnar recombination are too small for CFD simulation. We solve an ion transport equation during the period of columnar recombination with diffusion and recombination terms and incorporated the relation between ion loss and turbulent parameters into CFD. Using this model, simulations have been done for various air speeds and targets. Those for simulation results agree with experiments, showing improvement of simulation accuracy.

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Computation of the Removal Function for Ion Beam Figuring Curved Surface

Journal of Computational and Theoretical Nanoscience ◽

10.1166/jctn.2016.5664 ◽

2016 ◽

Vol 13 (10) ◽

pp. 7025-7031 ◽

Cited By ~ 2

Author(s):

Wa Tang ◽

Weijie Deng ◽

Xiaolin Yin ◽

Donglin Xue ◽

Ligong Zheng ◽

...

Keyword(s):

Density Distribution ◽

Gaussian Distribution ◽

Material Removal ◽

Ion Beam ◽

Surface Profile ◽

Curved Surface ◽

Space Distribution ◽

Computation Method ◽

Ion Density ◽

Ion Beam Figuring

Ion beam figuring (IBF) is a deterministic method for final figuring process of optical surface. The removal functions of IBF should be measured and calibrated strictly to guarantee the accuracy of the figuring results. The incident parameters of ion, surface profile and ion density distribution on the surface are the main factors which affect the material removal rate within the removal function. For the curved surfaces these factors vary from point to point so that the removal functions keeps changing when figuring curved surface especially for steep surface. Unlike the first two factors, the ion density distribution can’t be described by mathematic expression directly. Moreover, the ion is not in Gaussian distribution on the curved surface any more, which will result in variation of removal functions. Faraday cup is used to get the ion space distribution. So that the ion density on an arbitrary point can be obtained exactly. Based on the material removal features, revision method is proposed to fix the difference of the removal functions between the curved surface and the flat surface. Through experiments and theoretical analysis, the removal functions changes distinctly and not in Gaussian distribution. The computation method can fit the variety of the removal function effectively.

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Beam divergence and ion density measurements for an induction coupled ion beam source

Review of Scientific Instruments ◽

10.1063/1.1143433 ◽

1992 ◽

Vol 63 (11) ◽

pp. 5234-5236

Author(s):

J. R. Pai ◽

N. Venkatramani

Keyword(s):

Ion Beam ◽

Beam Divergence ◽

Beam Source ◽

Ion Density ◽

Density Measurements

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Magnetic field configurations on thruster performance in accordance with ion beam characteristics in cylindrical Hall thruster plasmas

Applied Physics Letters ◽

10.1063/1.4978532 ◽

2017 ◽

Vol 110 (11) ◽

pp. 114101 ◽

Cited By ~ 8

Author(s):

Holak Kim ◽

Wonho Choe ◽

Youbong Lim ◽

Seunghun Lee ◽

Sanghoo Park

Keyword(s):

Magnetic Field ◽

Ion Beam ◽

Hall Thruster ◽

Beam Characteristics

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A Developed Structure for DC–DC Quasi-Z-Source Converter with High Voltage Gain and High Reliability

Journal of Circuits System and Computers ◽

10.1142/s0218126619500129 ◽

2018 ◽

Vol 28 (01) ◽

pp. 1950012 ◽

Cited By ~ 2

Author(s):

Ebrahim Babaei ◽

Mohammad Shadnam Zarbil ◽

Elias Shokati Asl

Keyword(s):

Computer Aided Design ◽

High Reliability ◽

Stage Structure ◽

The Other ◽

Voltage Gain ◽

Operating Modes ◽

High Voltage Gain ◽

Comprehensive Comparison ◽

Simulation Results ◽

Aided Design

In this paper, a developed structure for DC–DC quasi-Z-source (QZS) converters is proposed. First, the proposed two-stage structure is presented and analyzed. Then, the proposed structure is extended to [Formula: see text] stages and its relations are calculated. Compared with other conventional structures, the proposed structure has higher voltage gain and higher reliability. The proposed topology is suitable for high power applications. To have the correct performance of conventional QZS converter, all impedance network elements must be intact. In the case of small failure in one of the elements, the operation of the whole system is disrupted. The proposed structure has high reliability because when one stage fails, the fault management system separates that stage from the other stages and the remaining stages continue to transmit power. In this paper, in addition to analyzing the operation of the proposed converter in different operating modes, calculations of voltage gain, voltage stresses across capacitors and reliability analysis are also presented. Reliability is calculated according to well-known Markov model. Moreover, a comprehensive comparison in terms of voltage gain and reliability is made between the proposed converter and the other conventional structures. Also, the rating values of inductors and capacitors are designed. Finally, experimental and simulation results are presented by using power system computer-aided design (PSCAD) software to verify the theories.

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