Charge exchange recombination spectroscopy on the stellarator W7-AS
In the advanced stellarator W7-AS, active charge exchange recombination spectroscopy CXRS is performed on intrinsic plasma impurities. Measurements are done on the doublet lines of the singly charged species of HeII, BV, CVI, and NVII. A pulsed diagnostic neutral beam injector excites CX spectral lines in the visible or near UV region. By switching the beam off and on, the electron impact excited spectral light intensity from the cold plasma edge can be subtracted from the signal of interest. The spectral lines are observed after transmission by imaging mirrors and glass fibers by means of Czerny{endash}Turner monochromators with high spectral resolution of down to 0.3 {Angstrom} per spectral channel. A turnable mirror device allows for the observation at well defined spatial locations within the plasma. As detectors, photomultiplier arrays, and charge coupled device camera systems are used. By spectral measurement of the CX Doppler line intensity, line shift, and line broadening, we evaluate the impurity density and rotation velocity profile and the impurity ion temperature. These parameters provide the transport relevant radial electric field and the ion temperature profile. The radial ion particle and heat transport together with the ambipolar electric field play a decisive role for the optimization of the three-dimensional stellarator plasma. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 451942
- Report Number(s):
- CONF-960543-; ISSN 0034-6748; TRN: 97:006299
- Journal Information:
- Review of Scientific Instruments, Vol. 68, Issue 1; Conference: 11. annual high-temperature plasma diagnostics conference, Monterey, CA (United States), 12-16 May 1996; Other Information: PBD: Jan 1997
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PLASMA DIAGNOSTICS
CHARGE-COUPLED DEVICES
OPTICAL SPECTROMETERS
WENDELSTEIN-7 STELLARATOR
PLASMA IMPURITIES
PLASMA DENSITY
RECOMBINATION
CHARGE EXCHANGE
HELIUM IONS
BORON IONS
CARBON IONS
NITROGEN IONS
VISIBLE SPECTRA
ULTRAVIOLET SPECTRA
plasma toroidal confinement
plasma temperature
plasma transport processes
plasma-beam interactions