Effect of oscillating sheath on near-wall conductivity in Hall thrusters

Yu, Daren; Li, Hong; Wu, Zhiwen; Wei, Mao

doi:10.1063/1.2743024

Cited by 25 publications

(16 citation statements)

References 10 publications

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“…Meanwhile, as the works in Ref. [9,10,13] found that the surface erosion, oscillating sheath etc. can enhance the NWC effect, so the sheath effect on NWC becomes further weaker.…”

Section: Numerical Modelmentioning

confidence: 97%

“…Under these two NWC models, a current density peak was found near the channel wall. Later, these two models were subjected to many modifications and the results showed that NWC is infruenced by many factors, such as surface erosion, magnetic field gradient in radial direction, plasma wall recombination and oscillating sheath, etc [9][10][11][12][13]. All the previous models on NWC only considered that the magnetic field is perpendicular to the wall.…”

Section: Introductionmentioning

confidence: 97%

“…We use a test particle method as the Ref. [10,11,13] to describe the electron dynamics process in the plasma. Electrons are randomly emitted from the centerline towards the channel wall .…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Magnetic Mirror on Near Wall Conductivity in Hall Thrusters

Liu

Cao

et al. 2008

Contrib. Plasma Phys.

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The effect of magnetic mirror on near wall conductivity is studied in the acceleration region of Hall thrusters. The electron dynamics process in the plasma is described by test particle method, in which electrons are randomly emitted from the centerline towards the inner wall of the channel. It is found that the effective collision coefficient, i.e. the rate of electrons colliding with the wall, changes dramatically with the magnetic mirror effect being considered; and that it decreases further with the increase of magnetic mirror ratio to enhance the electron mobility accordingly. In particular, under anistropic electron velocity distribution conditions, the magnetic mirror effect becomes even more prominent. Furthermore, due to decrease in magnetic mirror ratio from the exhaust plane to the anode in Hall thrusters, the axial gradient of electron mobility with magnetic mirror effect is greater than without it. The magnetic mirror effects on electron mobility are derived analytically and the results are found in agreement with the simulation.

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“…Meanwhile, as the works in Ref. [9,10,13] found that the surface erosion, oscillating sheath etc. can enhance the NWC effect, so the sheath effect on NWC becomes further weaker.…”

Section: Numerical Modelmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

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The Effect of Magnetic Mirror on Near Wall Conductivity in Hall Thrusters

Liu

Cao

et al. 2008

Contrib. Plasma Phys.

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“…As addressed in Ref. [13], Δφ d is close to the corresponding steady-state Debye jump Δφ d , A doesn't exceed the magnitude of Δφ d , and f sh is equal to the electron plasma frequency of the near-wall region. In view that the plasma parameters those determine the electron plasma frequency have a non-uniform distribution along the thruster channel and given the various frequency bands of plasma instabilities from a general point of view, we extend the oscillation frequency to a considerable wide range for obtaining a comprehensive knowledge.…”

Section: Secondary Electron Motion Modelmentioning

confidence: 95%

Effect of Oscillating Sheath on Near‐Wall Electron Current Profile in Hall Thrusters

Liu²,

Ning

et al. 2008

Contrib. Plasma Phys.

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The radial profile of the axial electron current in Hall thrusters was measured; however, the significant decay of the current density peak in the near-wall region can't be explained effectively by the steady sheath theory. As the sheath exhibits an oscillating character when the thruster is in operation, its effect on the near-wall current profile has been studied in this paper. To obtain a comprehensive knowledge, we have considered a wide sheath oscillation frequency span which includes two asymptotic frequency cases at high and low ends. Based on the case studied, either an analytical treatment or a numerical simulation is applied. The results show that the current density peak has a fastest damping speed away from the wall at the asymptotic low frequency. With the increase of the frequency, both the decay and the spatial "wavelength" of the current profile decrease. The decay finally disappears at the asymptotic high frequency with a constant spatial "wavelength". Moreover, the sheath oscillation amplitude can enhance the decay and enlarge the spatial "wavelength". Taking into account of the realistic situation in Hall thrusters, the significant impact of the oscillating sheath on the near-wall electron current profiles can be anticipant.

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“…Hall thruster simulations reveal sheath instabilities that abruptly alter the state of the plasma [9] and drive oscillations [10,11]. Sheath oscillations may considerably increase near-wall conductivity in HT's [10,12] and cause interference [13]. However, the precise causes and conditions for sheath instability are not yet quantified.…”

mentioning

confidence: 99%

General Cause of Sheath Instability Identified for Low Collisionality Plasma in Devices with Secondary Electron Emission

Campanell¹

2012

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Effect of oscillating sheath on near-wall conductivity in Hall thrusters

Cited by 25 publications

References 10 publications

The Effect of Magnetic Mirror on Near Wall Conductivity in Hall Thrusters

The Effect of Magnetic Mirror on Near Wall Conductivity in Hall Thrusters

Effect of Oscillating Sheath on Near‐Wall Electron Current Profile in Hall Thrusters

General Cause of Sheath Instability Identified for Low Collisionality Plasma in Devices with Secondary Electron Emission

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