Characterization of hollow cathode and parallel plate microplasmas: scaling and breakdown

J Greenan, CMO Mahony, D Mariotti, PD Maguire

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

We present an experimental comparison of parallel plate and hollow cathode microplasma structures, operated at high pressure with narrow anode�cathode gaps. A moveable anode arrangement with ±12 µm spatial resolution was used to vary the electrode separation to cover the pd range between 0.01 and 4 Torr cm for both structures. The hollow cathode discharge was operated with pressure�diameter ( pD ) product values between 1.8 and 7.2 Torr cm and an aspect ratio of ~5. Analysis of V � I characteristics shows j / p 2 and j 2 p scaling for low and high current modes, respectively. Electron temperature estimates between 2 and 3 eV were obtained by solving a numerical collisional�radiative model based on transitions from 4p argon levels. The hollow cathode sheath thickness for both ionizing and non-ionizing sheath conditions was determined analytically and the diffusion equation was solved numerically to estimate the plasma density profile for the ionizing sheath case.
LanguageEnglish
Pages025011
JournalPlasma Sources Science and Technology
Volume20
Issue number2
Publication statusPublished - 23 Mar 2011

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microplasmas
hollow cathodes
parallel plates
sheaths
breakdown
scaling
cathodes
low currents
estimates
plasma density
high current
aspect ratio
anodes
spatial resolution
argon
electron energy
electrodes
products
profiles

Cite this

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abstract = "We present an experimental comparison of parallel plate and hollow cathode microplasma structures, operated at high pressure with narrow anode{\^a}��cathode gaps. A moveable anode arrangement with {\^A}±12 {\^A}µm spatial resolution was used to vary the electrode separation to cover the pd range between 0.01 and 4 Torr cm for both structures. The hollow cathode discharge was operated with pressure{\^a}��diameter ( pD ) product values between 1.8 and 7.2 Torr cm and an aspect ratio of ~5. Analysis of V {\^a}�� I characteristics shows j / p 2 and j 2 p scaling for low and high current modes, respectively. Electron temperature estimates between 2 and 3 eV were obtained by solving a numerical collisional{\^a}��radiative model based on transitions from 4p argon levels. The hollow cathode sheath thickness for both ionizing and non-ionizing sheath conditions was determined analytically and the diffusion equation was solved numerically to estimate the plasma density profile for the ionizing sheath case.",
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Characterization of hollow cathode and parallel plate microplasmas: scaling and breakdown. / Greenan, J; Mahony, CMO; Mariotti, D; Maguire, PD.

In: Plasma Sources Science and Technology, Vol. 20, No. 2, 23.03.2011, p. 025011.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Characterization of hollow cathode and parallel plate microplasmas: scaling and breakdown

AU - Greenan, J

AU - Mahony, CMO

AU - Mariotti, D

AU - Maguire, PD

PY - 2011/3/23

Y1 - 2011/3/23

N2 - We present an experimental comparison of parallel plate and hollow cathode microplasma structures, operated at high pressure with narrow anode�cathode gaps. A moveable anode arrangement with ±12 µm spatial resolution was used to vary the electrode separation to cover the pd range between 0.01 and 4 Torr cm for both structures. The hollow cathode discharge was operated with pressure�diameter ( pD ) product values between 1.8 and 7.2 Torr cm and an aspect ratio of ~5. Analysis of V � I characteristics shows j / p 2 and j 2 p scaling for low and high current modes, respectively. Electron temperature estimates between 2 and 3 eV were obtained by solving a numerical collisional�radiative model based on transitions from 4p argon levels. The hollow cathode sheath thickness for both ionizing and non-ionizing sheath conditions was determined analytically and the diffusion equation was solved numerically to estimate the plasma density profile for the ionizing sheath case.

AB - We present an experimental comparison of parallel plate and hollow cathode microplasma structures, operated at high pressure with narrow anode�cathode gaps. A moveable anode arrangement with ±12 µm spatial resolution was used to vary the electrode separation to cover the pd range between 0.01 and 4 Torr cm for both structures. The hollow cathode discharge was operated with pressure�diameter ( pD ) product values between 1.8 and 7.2 Torr cm and an aspect ratio of ~5. Analysis of V � I characteristics shows j / p 2 and j 2 p scaling for low and high current modes, respectively. Electron temperature estimates between 2 and 3 eV were obtained by solving a numerical collisional�radiative model based on transitions from 4p argon levels. The hollow cathode sheath thickness for both ionizing and non-ionizing sheath conditions was determined analytically and the diffusion equation was solved numerically to estimate the plasma density profile for the ionizing sheath case.

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