ELM-induced arcing on tungsten fuzz in the COMPASS divertor region

TitleELM-induced arcing on tungsten fuzz in the COMPASS divertor region
Publication TypeJournal Article
Year of Publication2017
AuthorsJ. Matejicek, V. Weinzettl, M. Vilémová, T.W Morgan, G. De Temmerman, M. Dimitrova, J. Cavalier, J. Adamek, J. Seidl, A. Jager
JournalJournal of Nuclear Materials
Volume492
Pagination204-212
Date Published08/2017
Abstract

Materials exposed to plasma may undergo various forms of surface modifications. Among the important phenomena for tungsten - as the prime candidate plasma-facing material for fusion devices – is a formation of helium-induced fibreform nanostructure, so-called tungsten fuzz. In this paper, we report direct observations of the interaction of the pre-prepared fuzzy tungsten surfaces with ELMy H-mode plasmas in the COMPASS tokamak as well as consequent ex-situ morphological analyses, with a particular focus on arcing as a potential erosion mechanism. Arcing events are documented from high-speed camera imaging. The sample surfaces are examined by scanning electron microscopy. Arc traces were observed on all samples, while their number was dependent on the sample position and orientation. Inside the arc traces, localized melting and densification of the original fuzz was observed, resulting in thickness reduction. The modified structure still retained some porosity and did not extend into the bulk.

DOI10.1016/j.jnucmat.2017.05.032
Division

PSI

Department

PSI-E

PID

ecfe44302c77f81c546b49574e29a7a3

Alternate TitleJ. Nucl. Mater.

Go back one page.