A flowing plasma model to describe drift waves in a cylindrical helicon discharge

Chang, Lei; Hole, Matthew; Corr, Cormac

doi:10.1063/1.3581045

Cited by 11 publications

(16 citation statements)

References 42 publications

(58 reference statements)

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“…As pointed earlier, the radial density gradient and accordingly edge density have an important effect on the non-resonant mode conversion of helicon wave into Trivelpiece-Gould wave and power absorption, we thereby choose these two density profiles with very different radial gradients. [20] The density level of 10 18 m −3 is also typical for helicon discharges [21,22,23,24,25]. All computed results are normalized to antenna current of 1 A, therefore, the presented power absorptions are relative results.…”

Section: Theoretical Model and Computational Schemementioning

confidence: 99%

Coupling of RF antennas to large volume helicon plasma

Chang

Gao

et al. 2018

AIP Advances

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Large volume helicon plasma sources are of particular interest for large scale semiconductor processing, high power plasma propulsion and recently plasmamaterial interaction under fusion conditions. This work is devoted to studying the coupling of four typical RF antennas to helicon plasma with infinite length and diameter of 0.5 m, and exploring its frequency dependence in the range of 13.56 − 70 MHz for coupling optimization. It is found that loop antenna is more efficient than half helix, Boswell and Nagoya III antennas for power absorption; radially parabolic density profile overwhelms Gaussian density profile in terms of antenna coupling for low-density plasma, but the superiority reverses for high-density plasma. Increasing the driving frequency results in power absorption more near plasma edge, but the overall power absorption increases with frequency. Perpendicular stream plots of wave magnetic field, wave electric field and perturbed current are also presented. This work can serve as an important reference for the experimental design of large volume helicon plasma source with high RF power.

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Section: Theoretical Model and Computational Schemementioning

confidence: 99%

Coupling of RF antennas to large volume helicon plasma

Chang

Gao

et al. 2018

AIP Advances

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“…Overall, the normalized frequency is lower on MEVAT for F > 0.4, which may be attributed to lower rotation frequency and ion temperature as revealed in a previous study. 18…”

Section: B Dispersion Relationmentioning

confidence: 99%

“…[7][8][9][10][11][12] Due to the nonuniform configurations of equilibrium magnetic field, discharge area and plume, plasma rotation driven by Lorentz force commonly occurs in various electric thrusters. [13][14][15][16] A few analytical models have been developed or/and applied to describe this flowing phenomenon, [17][18][19][20][21] but little attention was given to the resulted plasma instability which, however, can effect the propulsion efficiency, precise control, durable reliability and life time significantly. 22,23 This paper considers an emerging plasma propulsion technology, namely magnetically enhanced vacuum a) Electronic mail: leichang@scu.edu.cn arc thruster (MEVAT), [24][25][26][27][28] as an example and studies the instability evolution caused by plasma rotation and axial flow in detail.…”

Section: Introductionmentioning

confidence: 99%

Plasma instability of magnetically enhanced vacuum arc thruster

Chang

Zhang²,

et al. 2019

AIP Advances

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A two-fluid flowing plasma model is applied to describe the plasma rotation and resulted instability evolution in magnetically enhanced vacuum arc thruster (MEVAT). Typical experimental parameters are employed, including plasma density, equilibrium magnetic field, ion and electron temperatures, cathode materials, axial streaming velocity, and azimuthal rotation frequency. It is found that the growth rate of plasma instability increases with growing rotation frequency and field strength, and with descending electron temperature and atomic weight, for which the underlying physics are explained. The radial structure of density fluctuation is compared with that of equilibrium density gradient, and the radial locations of their peak magnitudes are very close, showing an evidence of resistive drift mode driven by density gradient. Temporal evolution of perturbed mass flow in the cross section of plasma column is also presented, which behaves in form of clockwise rotation (direction of electron diamagnetic drift) at edge and anti-clockwise rotation (direction of ion diamagnetic drift) in the core, separated by a mode transition layer from n = 0 to n = 1. This work, to our best knowledge, is the first treatment of plasma instability caused by rotation and axial flow in MEVAT, and is also of great practical interest for other electric thrusters where rotating plasma is concerned for long-time stable operation and propulsion efficiency optimization.

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“…The bifurcation of these structures was also investigated in their model. Chang et al [243] applied a twofluid model to interpret plasma oscillations in the WOBAT device. They showed that the density and space potential profiles agreed with their experimental results, but the temperature profile was not flat in the observed results, as assumed by the model.…”

Section: Attempts For Self Consistent Modelmentioning

confidence: 99%

Review of Helicon High-Density Plasma: Production Mechanism and Plasma/Wave Characteristics

Isayama

Shinohara

Hada

2018

Plasma and Fusion Research

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Helicon plasma is one of the radio frequency plasma source that can generate high-density and lowtemperature plasmas by utilizing the helicon wave, i.e., the electromagnetic whistler wave in a bounded geometry. Helicon plasma is very useful for various applications due to its extremely efficient production of high-density plasma. Conversely, many unsolved physical issues remain regarding how an efficient production of the helicon plasma is realized in laboratories and what determines the density maximum. The past decades of the helicon studies have revealed that the "Trivelpiece-Gould" wave is responsible for the efficient power absorption. In recent years, the drift-wave type and the parametric-decay instabilities have been extensively studied, by using the linear magnetized helicon plasma sources. The present helicon study considers these non-linear effects. Consequently, it includes many interests for both industry and research fields. The mechanism of the helicon production is discussed, based on the several critical physical issues. In addition, some recent topics and the efforts to build a more refined physical model of the helicon plasma are highlighted.

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A flowing plasma model to describe drift waves in a cylindrical helicon discharge

Cited by 11 publications

References 42 publications

Coupling of RF antennas to large volume helicon plasma

Coupling of RF antennas to large volume helicon plasma

Plasma instability of magnetically enhanced vacuum arc thruster

Review of Helicon High-Density Plasma: Production Mechanism and Plasma/Wave Characteristics

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