Plasma and Fusion Research

Volume 16, 2405069 (2021)

Regular Articles

Enhancement of Arc Ignition on Tungsten in Helium Plasmas with Impurity Gases
Rongshi ZHANG, Shin KAJITA1), Dogyun HWANGBO2), Hirohiko TANAKA and Noriyasu OHNO
Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
1)
Institute of Materials and Sustainable Systems, Nagoya University, Nagoya 464-8603, Japan
2)
Faculty of Pure and Applied Sciences, University of Tsukuba, Ibaraki 305-8577, Japan
(Received 16 November 2020 / Accepted 2 April 2021 / Published 24 May 2021)

Abstract

Arcing was ignited on deformed tungsten (W) surfaces, where W fuzz and/or nano-tendril bundles (NTBs) were grown, by steady state helium (He) plasma exposures with impurity gas seeding. At the same sample potential of −250V, the presence of NTBs enhanced the frequency of arc ignition, whereas no arc ignition appeared on typical fuzz surfaces without NTBs. After a series of arc ignitions on a sample surface with NTBs, the aspect ratio of NTBs decreased, indicating that protruded NTBs with larger aspect ratio tend to trigger arcing easily.

Keywords

tungsten, unipolar arc, nano-tendril bundles, impurity seeding, fuzz

DOI: 10.1585/pfr.16.2405069

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