Speaker
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http://ocs.ciemat.es/EPS2019ABS/pdf/P2.1009.pdfAn analysis is carried out of the possibility of using the high-resolution spectroscopy (HRS)
data, specifically, the asymmetry of the spectral line shape of the radiation emitted in the
Balmer-alpha lines of hydrogen isotopes, to recover the flux of neutral hydrogen atoms and
molecules from the tokamak first wall to the SOL plasma in real time measurements. To this
end, a new method is proposed, which generalizes the well-known SXB method [1, 2], widely
used for recovery the impurity atoms/ions fluxes from wavelength-integrated spectral line
measurements, to the case of hydrogen. The proposed modification is motivated by the
impossibility of reliable interpretation of molecular spectra in the ITER main chamber
because of a strong background light from the divertor. The method makes it possible to
replace the equation corresponding to the DXB method for molecular spectra with another
equation using the relation between the asymmetry of the line shape of spectral intensity and
the atomic flux density. The method uses atomic and molecular flux density profiles,
simulated [3] with the modified Ballistic Model [4]. The modified SXB method is tested by
comparing the results with the data for deuterium neutral atom velocity distribution in the
SOL from the EIRENE code [5] stand-alone simulations [6] on the background plasma
modeled by the SOLPS code [7] with extended to the wall numerical mesh [8], for six
modelled types of the SOL plasma profiles in ITER (these data were used in synthetic H-
alpha diagnostics [9] based on solving a multiparametric inverse problem). The limitations
of the method are discussed, including the problem [9] of selecting the HRS signal from the
SOL under condition of a strong divertor stray light in ITER.
References
[1]. Behringer K. H., J. Nucl. Mater., 1987, 145147, 145. [2]. Pospieszczyk A., et al., J. Phys. B: At. Mol. Opt. Phys., 2010, 43, 144017. [3]. Neverov V.S., private communications, 2018. [4]. Kadomtsev M.B., et al., Eur. Conf. Abstracts, 2012, vol. 36F, P4.093. [5]. Reiter D., et al., Fusion Sci. Technol., 47, 172 (2005). [6]. Lisgo S. W., et al., private communications, 2012. [7]. Kukushkin A.S., et al., Fusion Eng. Des. 86, 2865 (2011). [8]. Lisgo S. W., et al., J. Nucl. Mater., 415, 965 (2011). [9]. Kukushkin A.B., Neverov V.S., et al., Fusion Sci. Tech., 2016, 69, 628.
