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Title: On vapor shielding of dust grains of iron, molybdenum, and tungsten in fusion plasmas

The shielding effects of ablation cloud around a small dust grain composed of iron, molybdenum, or tungsten in fusion plasmas are considered. These include collisional dissipation of momentum flux of impinging plasma ions, heat transfer by secondary plasma created due to electron impact ionization of the ablated atoms, and radiative plasma power losses in the ablation cloud. The maximum radius, which limits applicability of existing dust-plasma interaction models neglecting the cloud shielding effects, for dust grains of the considered high-Z metals is calculated as function of plasma parameters. The thermal bifurcation triggered by thermionic electron emission from dust grains, observed for some of the considered materials, is analyzed. The results are compared with previous calculations for dust composed of low-Z fusion related materials, i.e., lithium, beryllium, and carbon.
Authors:
; ;  [1]
  1. Department of Mechanical and Aerospace Engineering, University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093-0411 (United States)
Publication Date:
OSTI Identifier:
22252040
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ABLATION; BERYLLIUM; CARBON; ELECTRON EMISSION; HEAT TRANSFER; IONIZATION; IONS; IRON; LITHIUM; MATERIALS; MOLYBDENUM; PLASMA; POWER LOSSES; SHIELDING; TUNGSTEN; VAPORS