A charge exchange recombination spectroscopy (CXRS) diagnostic has been established on JET to study fully stripped low-Z species. Ion temperature in the plasma centre is measured from visible lines of helium, carbon and oxygen excited by charge exchange with heating neutral beam particles. Coincident cold components produced at the plasma edge are apparent on helium and carbon spectra and inost spectra are subject to accidental blending from other species' edge plasma emission. The charge exchange feature can be isolated from the various composite lines and all three impurities agree on the same temperature within experimental error. Observed column emissivities are converted into absolute impurity densities using a neutral beam attenuation code and charge exchange effective rate coefficients. Comprehensive new calculations have been performed to obtain the effective rate coefficients. The models take detailed account of cascading and the influence of the plasma environment in causing I-mixing, and allow the n-dependence of the rate coefficients to be addressed experimentally. The effective ion charge reconstructed from simultaneous measurements of the densities of dominant impurities shows good agreement with the value inferred from visible Bremsstrahlung. Some illustrative results are shown for helium (helium discharge or minority r.f. heating), carbon and oxygen concentrations monitored during characteristic operating regimes.
Observations are reported of resolved components of deuterium Balmer emission in neutral beam heated JET plasmas. The features are interpreted as Doppler-shifted emission from deuterium in the neutral beams spectrally resolved into components by the nu *B motional Stark electric field. The mechanisms of excitation of the deuterium are elucidated and the emission modelled. Attention is drawn to the diagnostic potential of the observations for measurement of local magnetic fields, deuteron density and effective plasma ion charge.
Calibration of the charge exchange recombination spectroscopy diagnostic for core poloidal rotation velocity measurements on JET Rev. Sci. Instrum. 75, 3452 (2004); 10.1063/1.1784531Real-time analysis of charge-exchange spectroscopy data at JET Recent developments and results of the JET CXRS diagnostic are reported. The measurements of radial profiles of ion temperatures and densities are based on CXR spectra of fully stripped ions of either carbon or beryllium. Considerable effort has been expended in ensuring consistency between radial profiles of low Z impurity densities and those from other diagnostics. The contributions of the main light impurities are used to reconstruct radial profiles of Zeffwhich can be compared with Abel-inverted signals from visible bremsstrahlung or soft x-ray emission. Active Balmer-Alpha spectroscopy (ABAS) is being introduced as a diagnostic tool providing data on local magnetic fields, neutral beam densities, and dilution factors. The effects of collision-energy-depcndcnt eXR cross sections on observed eXR spectra are calculated. Corrections for t.he values of deduced ion temperatures, toroidal velocities, and impurity densities are discussed for the case of plasmas with high ion temperatures and high toroidal rotation velocities. Some recent results of the JET 1989 operation illustrating the eXRS diagnostic potential are given.
It has been shown recently that the perovskite oxide SrVO3 is a transparent conductor with optical and electrical properties outreaching those of the most used material indium tin oxide (ITO). These properties, observed in the crystalline phase, imply the strong potential of SrVO3 for use as a lower cost alternative to ITO, but the possible integration of this perovskite oxide material in actual electronic devices is still an open question. One of the possible approaches for the integration of oxide materials is the use of amorphous thin films, allowing low thermal budgets to preserve the performances of the electronic device. Therefore, in this study, the electrical and optical properties of amorphous or poorly crystallized thin SrVO3 films are investigated.
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