Shi_Kong_AJP_2005.pdf (144.81 kB)
Mechanisms of the alpha and gamma modes in radio-frequency atmospheric
journal contribution
posted on 2009-08-20, 11:49 authored by J.J. Shi, Michael G. KongLarge-volume and uniform atmospheric glow discharges are finding a vast range of processing
applications, many of which have been traditionally addressed with the vacuum plasma technology.
When excited at kilohertz or above, these atmospheric plasmas operate typically at low current
densities below 30 mA/cm2 and often they are perceived to have very similar properties regardless
of their operation conditions. Recently a radio-frequency (rf) atmospheric glow discharge was
observed at high current density of up to 1 A/cm2, thus suggesting a previously overlooked and
potentially different operation regime. Through a computational study of rf atmospheric glow
discharges over a wide range of current density, this paper presents evidence of at least two glow
modes, namely, the α mode and the γ mode. It is shown that gas ionization in the α mode is
volumetric occurring throughout the electrode gap whereas in the γ mode it is dominated by
localized events near the boundary between the sheath and the plasma bulk. Secondary electron
emission strongly influences gas ionization in the γ mode yet matters little in the α mode. These
findings suggest a wider operation range of atmospheric glow plasmas than previously believed. The
contrasting dynamic behaviors of the two glow modes highlight both the potential to preferentially
match the operation regime of atmospheric glow discharges to the specific requirements of their
intended applications and the importance to develop diagnostics strategies appropriate for their
operation regimes.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Citation
Shi, J.J. and Kong, M.G., 2005. Mechanisms of the α and γ modes in radio-frequency atmospheric glow discharges. Journal of Applied Physics, 97 (2), article 023306, pp. 1-6.Publisher
© American Institute of PhysicsVersion
- VoR (Version of Record)
Publication date
2005Notes
Copyright 2005 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the authors and the American Institute of Physics. This article appeared in the Journal of Applied Physics and may be found at: http://link.aip.org/link/?JAPIAU/97/023306/1ISSN
0021-8979Language
- en