Thomson scattering diagnostics of SF6 gas-blasted arcs confined by a nozzle under free-recovery conditions

Kentaro Tomita, Daisuke Gojima, Takahiro Shimizu, Kiichiro Uchino, Tomoyuki Nakano, Yasunori Tanaka, Katsumi Suzuki, Takanori Iijima, Takeshi Shinkai

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19 Citations (Scopus)

Abstract

Collective Thomson scattering has been applied to gas-blasted arcs confined by a nozzle to measure their decay processes with respect to electron density (ne). Pure SF6 gas, an Ar/SF6 gas mixture (SF6 was 20, 40, 60, and 80% of the mixture), and pure Ar gas were used as arc-quenching media at atmospheric pressure. Copper-tungsten (40% copper) electrodes were installed inside a polytetrafluoroethylene (PTFE) nozzle and 50 mm-long gap arcs were generated between the electrodes. First, steady-state arcs were generated with 50 A current. Then, a semiconductor switch removed the arc current. It was found that after the current decreased to zero, ne exponentially decreased and the decay time constant of ne systematically decreased with an increasing SF6 gas ratio. Thomson scattering measured ne in the range 1021-1023 m-3. Self-emission measurements, which were performed with a high-speed camera at 200 000 frames per second, exhibited good agreement with the results of the Thomson scattering.

Original languageEnglish
Article number265201
JournalJournal of Physics D: Applied Physics
Volume48
Issue number26
DOIs
Publication statusPublished - Jul 8 2015

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

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