Journal ArticleDOI
Discharge equilibrium of a helicon plasma
Isaac D Sudit,Francis F. Chen +1 more
TLDR
In this article, the axial dependence of the plasma density, electron temperature, plasma potentials, and the 488 nm argon ion emission intensity have been measured in argon helicon discharges excited by both right helical and Nagoya III antennas for various magnitudes and directions of the magnetic field B.Abstract:
The axial dependence of the plasma density, electron temperature, plasma potentials, and the 488 nm argon ion emission intensity have been measured in argon helicon discharges excited by both right helical and Nagoya III antennas for various magnitudes and directions of the magnetic field B. The plasma parameters were monitored with RF-compensated probes, while the emission line was detected with an optical emission spectrometer that incorporates an optical fibre and a miniature lens. The right helical antennas were designed to excite the m = +1 azimuthal mode when B is parallel () to the propagation vector k, and the m = -1 mode when B is antiparallel (#) to k. The plasma is found to be more dense in the former case (, m = +1), and the density peaks several antenna lengths downstream in the k direction. Nagoya III antennas are symmetric antennas that should excite the same azimuthal mode content in either magnetic field direction; indeed, the light profile was found to be independent of field direction. In the near field, under the antennas, the density is approximately the same for both antenna geometries and magnetic field directions. These results indicate that the m = +1 mode is preferentially excited regardless of the antenna helicity.read more
Citations
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Journal ArticleDOI
Helicons-the past decade
Francis F. Chen,Roderick Boswell +1 more
TL;DR: In this paper, the authors investigated the physical mechanisms of magnetized radio-frequency discharges and the dominance of the right-hand polarized mode over the left-hand one, and the most recent results indicate that a nonobvious resolution of these problems is at hand.
Journal ArticleDOI
Physics of helicon discharges
TL;DR: In this article, low-pressure discharges ionized by helicon waves are studied for their possible use in cluster tools for the fabrication of next-generation computer chips, and applications of helicon discharges to such diverse fields as plasma accelerators, microwave generators and tokamak physics are illustrated.
Journal ArticleDOI
Generalized theory of helicon waves. I. Normal modes
Francis F. Chen,Donald Arnush +1 more
TL;DR: In this paper, the theory of helicon wave was extended to include finite electron mass and an electron cyclotron or Trivelpiece-Gould (TG) wave with a short radial wavelength was introduced.
Journal ArticleDOI
Upper Limit to Landau Damping in Helicon Discharges
Francis F. Chen,David Blackwell +1 more
TL;DR: In this article, an energy analyzer that accounts for rf fluctuations in plasma potential was constructed, and it was shown that Landau-accelerated electrons are too sparse to explain the ionization efficiency.
Journal ArticleDOI
The role of Trivelpiece–Gould waves in antenna coupling to helicon waves
TL;DR: In this article, the role of Trivelpiece-Gould (TG) modes has been clarified for nonuniform density, and a new algorithm is developed to treat the case of high magnetic fields, when the wave equation becomes singular.
References
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Book
Principles of Plasma Discharges and Materials Processing
TL;DR: In this paper, the authors introduce the concept of particle and energy balance in discharges and introduce the theory of collision dynamics and wave-heated discharges, as well as chemical reactions and equilibrium.
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Transport Properties of Gaseous Ions over a Wide Energy Range
TL;DR: In this paper, the authors presented a compilation of experimental ionic mobility data available in February 1976 and also presented data on ionic diffusion coefficients obtained from the time of the first good measurements up to August 1978.
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Plasma ionization by helicon waves
TL;DR: In this article, the dispersion relation for helicon waves in a uniform, bounded plasma is derived with both collisional and Landau damping, and it is shown that the latter can explain the very high absorption efficiency of helicon wave in plasma sources and can lead to plasma generators with a controlled primary electron energy.
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Very efficient plasma generation by whistler waves near the lower hybrid frequency
TL;DR: In this paper, it was shown that r.f. power at frequencies near the lower hybrid frequency couples resonantly into a standing whistler wave for an input power flux of less than 5 W cm 2 densities above 1012 cm-3 with close to 100% ionization.
Journal ArticleDOI
RF compensated probes for high-density discharges
Isaac D Sudit,Francis F. Chen +1 more
TL;DR: In this paper, a Langmuir probe for the study of high-density RF discharges has been developed and tested in a helicon discharge in which the RF potential (approximately=100 V) is much larger than the electron temperature (approximately = 4 eV).