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Title: A resistively heated CeB{sub 6} emissive probe

The plasma potential, V{sub p}, is a key quantity in experimental plasma physics. Its spatial gradients directly yield the electrostatic field present. Emissive probes operating under space-charge limited emission conditions float close to V{sub p} even under time-varying conditions. Throughout their long history in plasma physics, they have mostly been constructed with resistively heated tungsten wire filaments. In high density plasmas (>10{sup 12} cm{sup −3}), hexaboride emitters are required because tungsten filaments cannot be heated to sufficient emission without component failure. A resistively heated emissive probe with a cerium hexaboride, CeB{sub 6}, emitter has been developed to work in plasma densities up to 10{sup 13} cm{sup −3}. To show functionality, three spatial profiles of V{sub p} are compared using the emissive probe, a cold floating probe, and a swept probe inside a plasma containing regions with and without current. The swept probe and emissive probe agree well across the profile while the floating cold probe fails in the current carrying region.
Authors:
; ; ;  [1]
  1. Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States)
Publication Date:
OSTI Identifier:
22392497
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 86; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; EMISSION; FILAMENTS; PLASMA DENSITY; PROBES; SPACE CHARGE; TUNGSTEN; WIRES