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Flow Velocity Measurements Using ChERS in the HSX Stellarator
Author(s) -
Briesemeister A.,
Zhai K.,
Anderson D. T.,
Anderson F.S. B.,
Lore J.,
Talmadge J. N.
Publication year - 2010
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.200900057
Subject(s) - stellarator , physics , plasma , flow velocity , line (geometry) , atomic physics , thermal velocity , spectroscopy , doppler effect , magnetic field , flow (mathematics) , wavelength , plasma diagnostics , symmetry (geometry) , computational physics , optics , mechanics , nuclear physics , geometry , mathematics , quantum mechanics , astronomy
A Charge Exchange Recombination Spectroscopy (ChERS) system has been used to measure the velocity, density, and temperature profiles of fully stripped carbon impurities in the Helically Symmetric eXperiment (HSX). Velocity measurements have been obtained by reversing the magnetic field between sets of shots in order to reverse the plasma flow velocity. This essentially doubles the Doppler shift of the measured photons. It also eliminates the need to accurately determine the exact wavelength of the unshifted emission line which can depend on plasma conditions. Because two viewing angles are used for each radial location, the velocity magnitude and direction can be determined. The intrinsic velocity is found to move primarily in the direction of quasihelical symmetry with a peak velocity ∼20 km/s. The velocity increases with increasing ECRH power (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)