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Title: Comment on 'A nonlinear global model of a dual frequency capacitive discharge' [Phys. Plasmas 13, 083501 (2006)]

Abstract

No abstract prepared.

Authors:
;  [1];  [2]
  1. University College, Oxford OX1 4BH (United Kingdom)
  2. (Germany)
Publication Date:
OSTI Identifier:
20960135
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 1; Other Information: DOI: 10.1063/1.2431355; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; HIGH-FREQUENCY DISCHARGES; NONLINEAR PROBLEMS; PLASMA; PLASMA SHEATH; RF SYSTEMS

Citation Formats

Allen, J. E., Annaratone, B. M., and Max-Planck Institut fuer Extraterrestrische Physik, D-85741 Garching. Comment on 'A nonlinear global model of a dual frequency capacitive discharge' [Phys. Plasmas 13, 083501 (2006)]. United States: N. p., 2007. Web. doi:10.1063/1.2431355.
Allen, J. E., Annaratone, B. M., & Max-Planck Institut fuer Extraterrestrische Physik, D-85741 Garching. Comment on 'A nonlinear global model of a dual frequency capacitive discharge' [Phys. Plasmas 13, 083501 (2006)]. United States. doi:10.1063/1.2431355.
Allen, J. E., Annaratone, B. M., and Max-Planck Institut fuer Extraterrestrische Physik, D-85741 Garching. Mon . "Comment on 'A nonlinear global model of a dual frequency capacitive discharge' [Phys. Plasmas 13, 083501 (2006)]". United States. doi:10.1063/1.2431355.
@article{osti_20960135,
title = {Comment on 'A nonlinear global model of a dual frequency capacitive discharge' [Phys. Plasmas 13, 083501 (2006)]},
author = {Allen, J. E. and Annaratone, B. M. and Max-Planck Institut fuer Extraterrestrische Physik, D-85741 Garching},
abstractNote = {No abstract prepared.},
doi = {10.1063/1.2431355},
journal = {Physics of Plasmas},
number = 1,
volume = 14,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • No abstract prepared.
  • The behavior of dual frequency capacitively coupled plasmas is investigated. Assuming a realistic reactor configuration represented by effective geometry factors and taking into account two separate sinusoidal voltage sources operating at different frequencies, an ordinary differential equation is derived which describes the nonlinear dynamics of such discharges. An exact analytical solution of the equation is presented and employed for a parameter study of the discharge current characteristics. Simulation results for various gas pressures (=various electron-neutral collision rates), various amplitude ratios of the two independent rf sources, and various integer frequency ratios are shown. When the two frequencies are comparable, surprisingmore » nonlinear effects are observed. Particular under study is the heating at the plasma series resonance, either by direct excitation or via the nonlinear electron resonance heating mechanism.« less
  • In their paper, the authors assume ambipolar diffusion across a magnetic field. This is not true in a strong field and in most practical applications. The actual ion transport may be much larger and entirely different from that calculated by the authors.
  • N. Sternberg, V. Godyak, and D. Hoffman [Phys. Plasmas 13, 063511 (2006)] have produced a detailed paper on a cylindrical plasma column in an axial magnetic field. The authors found that the radial component of the ion velocity, on leaving the plasma region, is the ion acoustic velocity. This is, of course, the Bohm velocity, but the authors did not comment on this fact. The Bohm criterion does appear to be of general validity, however, and perhaps a greater emphasis should have been given to this result.
  • It is well known that the plasma equations, with or without a magnetic field present, have a singularity at the point where the ions reach the ion sound speed. In his comment to our paper, J. E. Allen [Phys. Plasmas 14, 024701 (2007)] tries to explain that phenomenon by claiming that the Boltzmann electron distribution must hold near the boundary even for magnetized plasmas. His claim, however, contradicts the theoretical and numerical results of our paper, the results he seems to agree with.