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Title: [ital Z][sub eff] profiles measured by visible and soft x-ray bremsstrahlung arrays in TFTR (abstract)

Journal Article · · Review of Scientific Instruments; (United States)
DOI:https://doi.org/10.1063/1.1146310· OSTI ID:6700250
; ;  [1]
  1. Princeton University, Princeton, New Jersey 08543 (United States)

The [ital Z][sub eff] profiles from the tangential array of visible bremsstrahlung (VB) emission (5235 A) have shown several interesting features in TFTR. The observed [ital Z][sub eff] profile was flat during the ohmic phase and hollow during the neutral-beam heating phase. In order to crosscheck the measured [ital Z][sub eff] profiles from the VB array, a poloidal array which measures bremsstrahlung emission in the soft x-ray region has been analyzed. The analysis of array measurements in the two different spectral regions was performed on the same geometry determined from the Abel inversion of the electron density (interferometry). The two independent measurements of [ital Z][sub eff] profiles have been consistent with each other for most of the discharges in TFTR. However, in a discharge where the two measurements are inconsistent, the [ital Z][sub eff] profile deduced from the VB array indicates some degree of problems. In this paper, the detailed analysis of the bremsstrahlung array (both poloidal and tangential) measurements is presented. Particularly, the effects of geometry in the inversion process, such as a poloidal elongation of flux surfaces, are investigated.

DOE Contract Number:
AC02-76CH03073
OSTI ID:
6700250
Journal Information:
Review of Scientific Instruments; (United States), Vol. 66:1; ISSN 0034-6748
Country of Publication:
United States
Language:
English