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Title: Ion energy distribution and gas heating in the cathode fall of a direct-current microdischarge

Abstract

This paper reports on measurements of the ion energy distribution (IED) at the cathode of an argon dc microdischarge using energy-resolved molecular beam mass spectrometry. The measurements are conducted at a fixed pressure-electrode separation product (pd) of 1 cm Torr with a maximum discharge pressure of 20 Torr. The measured IED is compared to the theory of Davis and Vanderslice [W. D. Davis and T. A. Vanderslice, Phys. Rev. 131, 219 (1963)]. A higher pressure in a case of almost constant normalized current densities by pressure (Jp{sup -2}=0.080{+-}0.006 mAecm{sup -2} Torr{sup -2}) yields a lower ratio of the ion mean free path to the sheath thickness. The results in almost constant Jp{sup -2} case then indicate that a scaling law of Jp{sup -2} is no longer applicable for IED of microdischarge. Expected background gaseous temperatures from IEDs with the collisional Child law have reasonable increasing with increased current density (J) in both cases of almost constant Jp{sup -2} and a constant pressure of 10 Torr. Supported by temperature measurement by laser absorption spectroscopy, it is demonstrated that the expanded theory might be applicable also to microdischarges (Ar{approx}20 Torr) with temperature adjusting.

Authors:
;  [1]
  1. Mechanical Engineering Department, Stanford University, Stanford, California 94305-3032 (United States)
Publication Date:
OSTI Identifier:
20779245
Resource Type:
Journal Article
Journal Name:
Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics
Additional Journal Information:
Journal Volume: 73; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevE.73.046401; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1063-651X
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION SPECTROSCOPY; ARGON; CATHODES; CURRENT DENSITY; DIRECT CURRENT; ELECTRIC DISCHARGES; ENERGY SPECTRA; HEATING; IONS; MASS SPECTROSCOPY; MEAN FREE PATH; MOLECULAR BEAMS; PLASMA SHEATH; SCALING LAWS; TEMPERATURE MEASUREMENT; THICKNESS

Citation Formats

Ito, Tsuyohito, and Cappelli, Mark A. Ion energy distribution and gas heating in the cathode fall of a direct-current microdischarge. United States: N. p., 2006. Web. doi:10.1103/PHYSREVE.73.0.
Ito, Tsuyohito, & Cappelli, Mark A. Ion energy distribution and gas heating in the cathode fall of a direct-current microdischarge. United States. doi:10.1103/PHYSREVE.73.0.
Ito, Tsuyohito, and Cappelli, Mark A. Sat . "Ion energy distribution and gas heating in the cathode fall of a direct-current microdischarge". United States. doi:10.1103/PHYSREVE.73.0.
@article{osti_20779245,
title = {Ion energy distribution and gas heating in the cathode fall of a direct-current microdischarge},
author = {Ito, Tsuyohito and Cappelli, Mark A},
abstractNote = {This paper reports on measurements of the ion energy distribution (IED) at the cathode of an argon dc microdischarge using energy-resolved molecular beam mass spectrometry. The measurements are conducted at a fixed pressure-electrode separation product (pd) of 1 cm Torr with a maximum discharge pressure of 20 Torr. The measured IED is compared to the theory of Davis and Vanderslice [W. D. Davis and T. A. Vanderslice, Phys. Rev. 131, 219 (1963)]. A higher pressure in a case of almost constant normalized current densities by pressure (Jp{sup -2}=0.080{+-}0.006 mAecm{sup -2} Torr{sup -2}) yields a lower ratio of the ion mean free path to the sheath thickness. The results in almost constant Jp{sup -2} case then indicate that a scaling law of Jp{sup -2} is no longer applicable for IED of microdischarge. Expected background gaseous temperatures from IEDs with the collisional Child law have reasonable increasing with increased current density (J) in both cases of almost constant Jp{sup -2} and a constant pressure of 10 Torr. Supported by temperature measurement by laser absorption spectroscopy, it is demonstrated that the expanded theory might be applicable also to microdischarges (Ar{approx}20 Torr) with temperature adjusting.},
doi = {10.1103/PHYSREVE.73.0},
journal = {Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics},
issn = {1063-651X},
number = 4,
volume = 73,
place = {United States},
year = {2006},
month = {4}
}