[Table of Contents]

Plasma and Fusion Research

Volume 8, 2401028 (2013)

Regular Articles

Secondary Electron Emission from a Negatively Charged Spherical Dust Particle by Electron Incidence
Yukihiro TOMITA, Gakushi KAWAMURA, Zhihui HUANG1), Yudong PAN1) and Longwen YAN1)
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan
1)
Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, Sichuan, China
(Received 22 November 2012 / Accepted 8 March 2013 / Published 23 April 2013)

Abstract

Secondary electron emission (SEE) from a spherical metallic dust particle by electron incidence was analyzed according to the OML (Orbit Motion Limited) model. As the observed dust speed in fusion plasmas (< 100 m/s) is much slower than electron thermal speed, its effect to the SEE current is negligibly small. It is clarified that there is a window of electron temperature, where the ratio of the SEE current to the absorbed electron current exceeds unity; for graphite 80 eV < Te < 326 eV and the maximum of the ratio ∼ 1.10 at Te ∼ 165 eV, for tungsten 32 eV < Te, the maximum ∼ 2.47 at Te ∼ 358 eV. These excesses come from the inverse proportion of the incident angle to the dust particle.

Keywords

dust particle, secondary electron emission, electron impact, dust charge

DOI: 10.1585/pfr.8.2401028

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This paper may be cited as follows:

Yukihiro TOMITA, Gakushi KAWAMURA, Zhihui HUANG, Yudong PAN and Longwen YAN, Plasma Fusion Res. 8, 2401028 (2013).