Ultrafast spectroscopy diagnostic to measure localized ion temperature and toroidal velocity fluctuations


Uzun-Kaymak I. U. , Fonck R. J. , McKee G. R. , Schoenbeck N., Smith D., Winz G., ...More

REVIEW OF SCIENTIFIC INSTRUMENTS, vol.81, no.10, 2010 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 81 Issue: 10
  • Publication Date: 2010
  • Doi Number: 10.1063/1.3479114
  • Journal Name: REVIEW OF SCIENTIFIC INSTRUMENTS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Middle East Technical University Affiliated: Yes

Abstract

A dual-channel high-efficiency, high-throughput custom spectroscopic system has been designed and implemented at DIII-D to measure localized ion thermal fluctuations associated with drift wave turbulence. A large-area prism-coupled transmission grating and high-throughput collection optics are employed to observe C VI emission centered near lambda = 529 nm. The diagnostic achieves 0.25 nm resolution over a 2.0 nm spectral band via eight discrete spectral channels. A turbulence-relevant time resolution of 1 mu s is achieved using cooled high-speed avalanche photodiodes and ultralow-noise preamplifiers. The system sensitivity is designed to provide measurements of normalized ion temperature fluctuations on the order of delta T-i/T-i <= 1%. (C) 2010 American Institute of Physics. [doi:10.1063/1.3479114]