skip to main content

This content will become publicly available on November 14, 2017

Title: Secondary electron emission from plasma-generated nanostructured tungsten fuzz

Recently, several researchers (e.g., Q. Yang, Y.-W. You, L. Liu, H. Fan, W. Ni, D. Liu, C. S. Liu, G. Benstetter, and Y. Wang, Scientific Reports 5, 10959 (2015)) have shown that tungsten fuzz can grow on a hot tungsten surface under bombardment by energetic helium ions in different plasma discharges and applications, including magnetic fusion devices with plasma facing tungsten components. This work reports direct measurements of the total effective secondary electron emission (SEE) from tungsten fuzz. Using dedicated material surface diagnostics and in-situ characterization, we find two important results: (1) SEE values for tungsten fuzz are 40-63% lower than for smooth tungsten and (2) the SEE values for tungsten fuzz are independent of the angle of the incident electron. The reduction in SEE from tungsten fuzz is most pronounced at high incident angles, which has important implications for many plasma devices since in a negative-going sheath the potential structure leads to relatively high incident angles for the electrons at the plasma confining walls. Overall, low SEE will create a relatively higher sheath potential difference that reduces plasma electron energy loss to the confining wall. Thus the presence or self-generation in a plasma of a low SEE surface suchmore » as tungsten fuzz can be desirable for improved performance of many plasma devices.:7px« less
Authors:
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [3]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of California, Los Angeles, CA (United States)
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  3. Univ. of California, Los Angeles, CA (United States)
Publication Date:
OSTI Identifier:
1335459
Grant/Contract Number:
AC02-09CH11466; AF9550-09-1-0695; FA9550-11-1-0282; FA9550-14-1-0053; FA9550-14-10317
Type:
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 109; Journal Issue: 20; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Research Org:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Secondary emission; Tungsten; X-ray photoelectron spectroscopy; Sputtering; Plasma