title: A resistively heated CeB6 emissive probe.
abstract: The plasma potential, V(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(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(12) cm(-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, CeB6, emitter has been developed to work in plasma densities up to 10(13) cm(-3). To show functionality, three spatial profiles of V(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.affiliation: Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Martin
authors.affiliation: Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
authors.forename: J
authors.initials: J
authors.lastname: Bonde
authors.affiliation: Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
authors.forename: W
authors.initials: W
authors.lastname: Gekelman
authors.affiliation: Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
authors.forename: P
authors.initials: P
authors.lastname: Pribyl