A resistively heated CeB6 emissive probe

作者：Martin M J^*; Bonde J; Gekelman W; Pribyl P

来源：Review of Scientific Instruments, 2015, 86(5): 053507.

DOI：10.1063/1.4921838

The plasma potential, Vp, 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 Vp 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 1013 cm(-3). To show functionality, three spatial profiles of Vp 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.

• 出版日期2015-5