Resonances and anti-resonances of a plasma column in a helicon plasma source

Shamrai, K. P.; Taranov, V. B.

doi:10.1016/0375-9601(95)00435-6

Cited by 50 publications

(52 citation statements)

References 7 publications

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“…Antiresonances occur if either one of the basis function radial currents vanishes. 20 Thus, if for a given k, j 1,r (a)ϭ0 ͑equivalent to the simple helicon boundary condition for uniform plasma͒, only helicon waves are present and we recover Eq. ͑3.1͒.…”

Section: Relationship Of the Solutionsmentioning

confidence: 69%

The role of Trivelpiece–Gould waves in antenna coupling to helicon waves

Arnush¹

2000

Physics of Plasmas

130

108

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It is well known that the simple theory of helicon waves, in which the electron mass m e is neglected, is valid only if E z also vanishes, a condition which is not satisfied in experiment. Exact solutions of cold plasma theory with finite m e and E z predict the existence of additional highly damped Trivelpiece-Gould ͑TG͒ modes ͑H-TG theory͒, which can greatly modify the nature of helicon discharges. However, most experiments have been explained using only the simple theory for which the helicon waves are undamped. In that case, antenna-plasma-coupling calculations predict infinite resonances. To avoid this problem theorists have set E z ϭ0 and included finite m e effects ͑the TE-H theory͒. By comparing the TE-H theory with exact ͑i.e., closed form͒ solutions for uniform density, the role of TG modes has been clarified. To do so for nonuniform density, a new algorithm is developed to treat the case of high magnetic fields, when the wave equation becomes singular. The results show that, though the wave patterns are not greatly affected by TG modes except at low magnetic fields or near the radial boundary, the k z spectrum and radial profile of the energy deposition are greatly modified. In particular, the peaks in the TE-H-mode spectrum, which lead to predictions of erroneously high antenna loading, are suppressed and broadened by the TG modes which also produce high edge absorption. Both the TE-H and exact theories give maximum antenna loading for 1 2 m e (/k) 2 Ϸ10-100 eV, in contrast to several hundred electron volts predicted by the simple theory.

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Section: Relationship Of the Solutionsmentioning

confidence: 69%

The role of Trivelpiece–Gould waves in antenna coupling to helicon waves

Arnush¹

2000

Physics of Plasmas

130

108

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“…Initial theoretical investigations of helicon sources focused on the excitation of bounded whistler, helicon, waves and the dynamics of electrons in those waves. [10][11][12] Helicon waves are the faster phase velocity solution to the cold plasma dispersion relation. [10][11][12] Helicon waves are the faster phase velocity solution to the cold plasma dispersion relation.…”

Section: Introductionmentioning

confidence: 99%

Ion dynamics in helicon sources

et al. 2003

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Recent experiments have demonstrated that ion dominated phenomena, such as the lower hybrid resonance, can play an important role in helicon source operation. In this work, we review recent ion heating measurements and the role of the slow wave in heating ions at the edge of helicon. sources. We also discuss the relationship between parametrically driven waves and ion heating near the rf antenna in helicon sources. Recent measurements of parallel and rotational ion flows in helicon sources have important implications for particle confinement, instability growth, and helicon source operation. In this work we present new measurements of ion flows and summarize the important features of the flows.

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“…Then the redundant polarization does not arise, and the excitation of electrostatic wave is suppressed. This is the case if the plasma and wave parameters satisfy the condition of anti-resonance for the electrostatic wave excitation [20] Electrostatic waves excited at the plasma edge due to mode conversion propagate to the plasma centre and deposit energy via collisions. The depth of penetration is An electrostatic wave can penetrate into the bulk plasma at low magnetic fields only, Bo< B, [16].…”

Section: Propagation and Damping Of Waves In A Source Plasmamentioning

confidence: 99%

Quasistatic Plasma Sources : Physical Principles, Modelling Experiments, Application Aspects

Shamrai¹,

Aleksandrov²,

Bougrov³

et al. 1997

J. Phys. IV France

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Abstract. Magnetic field enhanced rf plasma sources excited by fiame-type antennas (quasistatic plasma sources) are treated theoretically and experimentally. The theoretical model predicts that a significant part of the rf power is absorbed in a source plasma via the excitation of quasi-electrostatic waves. The dependences of absorption on plasma density, external magnetic field, driving frequency, and source dimensions (scaling laws) are obtained.Special experiments on low-power rf signal absorption in a preformed dense plasma corroborate well the theo~y. Results of test experiments with different sources have shown that a behaviour of the discharge in quasistatic sources is in good agreement with theoretical predictions. Using this knowledge, a compact low-power ion source was designed and optimized. Detailed testing of its parameters has shown that this device has good prospects for use as an ion thruster, and for various materials processing applications.

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Resonances and anti-resonances of a plasma column in a helicon plasma source

Cited by 50 publications

References 7 publications

The role of Trivelpiece–Gould waves in antenna coupling to helicon waves

The role of Trivelpiece–Gould waves in antenna coupling to helicon waves

Ion dynamics in helicon sources

Quasistatic Plasma Sources : Physical Principles, Modelling Experiments, Application Aspects

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