Ignition and erosion of materials by arcing in fusion‐relevant conditions. Issue 6 (18th May 2018)

• Record Type: Journal Article
• Authors: Hwangbo, Dogyun; Kajita, Shin; Barengolts, Sergey A.; Tsventoukh, Mikhail M.; Kawaguchi, Shota; Mesyats, Vadim G.; Ohno, Noriyasu
• Other Names: Marandet Y. guestEditor.; Ciraolo G. guestEditor.; Rosato J. guestEditor.; Serre E. guestEditor.
• Is Part Of: Contributions to plasma physics. Volume 58:Issue 6/7/8(2018)
• Page Start: 608
• Page End: 615
• Publication Date: 2018-05-18
• Subjects: arcing -- divertor -- erosion -- explosive cathode spot -- nanostructure; Plasma (Ionized gases) -- Periodicals; Electronic journals; 530.44
• DOI: 10.1002/ctpp.201700157
• Languages: English
• ISSNs: 0863-1042

Abstract

Abstract : This study investigated the characteristics of arcing initiated on nanostructured fuzzy tungsten (W) surfaces in helium (He) plasmas. Under the same He plasma conditions, the relationship between arc voltage and current was characterized as linear due to plasma resistance across the He plasma from the target surface to the plasma source. Properties of the erosion caused by arcing were investigated by focusing on two parameters: arc current and fuzzy layer thickness. The erosion per charge was significantly dependent on the thickness of the fuzzy layer but did not depend on the arc current. Sample surface analysis revealed that drastic changes in arc spot grouping features were accompanied by the fuzzy layer thickness variation. The ecton model indicated that the erosion as ions does not play a main role, but mechanical destruction by momentum transfer from the explosive electron emission centre to neighbouring nanowires seems to enhance the erosion greatly.