NSTX Boundary Density Fluctuation Measurement by FIReTIP System with USN/LSN Configurations*
Abstract
The outermost edge channel of the Far Infra Red Tangential Interferometry and Polarimetry (FIReTIP) system provides absolutely calibrated density fluctuation information in the edge region of the plasmas including the scrape-off region. Recently upgraded time resolution up to 500 kHz and a visible interferometer system, enable measurement of semi-localized electron density fluctuations as well as the corresponding chordal density. The study of a higher fluctuation level when the ion grad B drift direction is away from the X-point due to the boundary turbulence modes such as the X-point mode claimed by BOUT code has been proposed via two different configurations (USN and LSN) on NSTX. In this paper, the edge channel FIReTIP measurement of density fluctuations together with the comparison of GPI data including L/H transition and ELM period of NSTX plasmas will be discussed.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 2004
- Bibcode:
- 2004APS..DPPJP1023L