Spectral Line Shapes problems in ITER diagnostics by

Spectral Line Shapes problems in ITER diagnostics by V. S. Lisitsa (National Research Center “Kurchatov Institute”) on behalf of NRC “Kurchatov Institute” group (A. B. Kukushkin, M. B. Kadomtsev, V. A. Krupin, M. G. Levashova, A. Medvedev, E. Mukhin, V. S. Neverov, V. A. Shurygin, K. Yu. Vukolov, )

Line broadening of hydrogen spectral lines in strongly diagnostics in plasmas Goals: isotope compositionmagnetized ITER plasma by Balmer spectroscopic measurements (H-alpha, H-beta spectral lines; estimations of background radiation for Thomson diagnostics in ITER Paschen (e. g. P 7) spectral line shape); Doppler shapes from CXRS-diagnostics. Method: Fast FFM numerical codes for line shapes in thermonuclear plasmas with strong magnetic fields combined with B 2 -EIRENE data for plasma parameters distribution along lines of sights. Users: • ITER H-alpha diagnostics , Yu. Alekseev, A. Medvedev et al. (Kurchatov, Russia); • ITER Thomson scattering diagnostics, E. Mukhin et al. (Ioffe, Russia); • ITER CXRS – diagnostics, S. Tugarinov, V. Krupin (NRINITI, Kurchatov, Russia).

Balmer lines spectroscopy in edge and divertor plasmas- problems to be solved – 1) plasma-atom interaction in broad domain of plasma parameters (Nneutral /Ne, changes in atomic kinetics and line broadening mechanisms for Balmer spectra); – 2) multi-population nature of spectra observed (relationship between reflected, cx and dissociated groups); – 3) effects of strong magnetic field on Stark line shapes and dependences of shapes on observation angles; – 4) radiation trapping in divertor plasma; – 5) turbulent fluctuations of plasma parameters on Balmer spectral lines intensities.

REFERENCES • • • FFM - Calisti A. , Mossé C. , Ferri S. , Talin B. , Rosmej F. , Bureyeva L. A. , Lisitsa V. S. Phys. Rev. E, 2010, 81, 016406 Magnetic fields - S. Ferri, A. Calisti, C. Mossé, B. Talin, M. A. Gigosos, M. A. Gonzalez and V. Lisitsa, Phys Rev E 84, 026407 (2011). Highly excited energy levels - Stambulchik E. , Maron Y. J. Phys. B: At. Mol. Opt. Phys. , 2008, 41, 095703 Strong fields - P. Fassbinder, W. Schweizer. Hydrogen atom in very strong magnetic and electric fields, Phys. Rev. A, v. 53, N 4 (1996) p. 21352139. ITER modeling -J. Rosato, V. Kotov and D. Reiter. Modelling of passive spectroscopy in the ITER divertor: the first hydrogen Balmer lines. J Phys. B: At. Mol. Opt. Phys. 43 (2010) 144024 (7 pp) Divertor + trapping - J. Rosato, D. Reiter, V. Kotov, Y. Marandet, H. Capes, L. Godbert-Mouret, M. Koubiti, and R. Stamm. Progress on Radiative Transfer Modelling in Optically Thick Divertor Plasmas. Contrib. Plasma Phys. 50, No. 3 -5, 398 – 403 (2010).

LINES OF SIGHT • • Plasma parameters along lines of sight: electron and neutral (Monte-Carlo modeling –B 2 - EIRENE code) densities and temperatures.

LINES OF SIGHT in ITER

Coordinates for plasma parameters modeling

Plasma parameters distribution on horizontal chord (external domain) SOLPS 4. 3 – code (A. S. Kukushkin et al. , Nuclear Fusion, 2009)

Neutral atoms distribution on horizontal chord (SOLPS 4. 3 )

D-alpha, D-beta emissivity on chorizontal chorde

Balmer H-beta line shapes in magnetized plasmas B = 5 T, Ne = 21014 cm-3, Te = 1 e. V observation perpendicular to B observation parallel to B S. Ferri, A. Calisti, C. Mosse, V. S. Lisitsa, B. Talin et al. , Universit´e de Provence-CNRS (Marseille, France) + Kurchatov Inst. (Moscow, Russia)

Balmer alpha line shapes in magnetized plasmas B = 4 T, Ne = 1014 cm-3, Te = 1 e. V Observation perpendicular to B S. Ferri, A. Calisti, C. Mosse, V. S. Lisitsa, B. Talin et al. , Universit´e de Provence-CNRS (Marseille, France) + Kurchatov Inst. (Moscow, Russia)

Balmer beta line shapes in magnetized plasmas B = 4 T, Ne = 1014 cm-3, Te = 1 e. V Observation perpendicular to B S. Ferri, A. Calisti, C. Mosse, V. S. Lisitsa, B. Talin et al. Universit´e de Provence-CNRS (Marseille, France) + Kurchatov Inst. (Moscow, Russia)

Total Line shape of hydrogen isotopes in SOL

Problem of SOL radiation blending by divertor intensity • Reflected divertor emissivity dominates SOL 2 -3 orders (!) of magnitude • Ticold =3 e. V • Tihot =50 e. V • Ti in edge plasma is larger than in divertor • Detail line shapes in divertor are needed for SOL emissivity observations (shapes for averaged plasma parameters or divertor averaged shapes!)

H-Alpha Fuel-Ratio & Particle Influx M. von Hellermann ITPA 2011 I-divertor: I-wall =10 T/D –div= T/D-wall =1 Ti cold = 3 e. V Ti hot = 50 e. V I-hot/I-cold fixed Error I-cold : 2. 8% Error T/D ratio : 0. 7 % ITPA Meeting Hefei, October 2011 16

Da image from JET

Polarization H-alpha measurements of H/D isotopes on Т-10 (A. Medvedev et al. ) Non-polarized spectra po D sдет, отн. ед. s-D s-H po H s+H l, Å Spectra image Line shape The curve contains six components: 1 - p and 2 - s hydrogen components 1 - p и 2 - s deiterium components s+D

Experimental spectra of H/D isotopes on Т-10 (A. Medvedtv et. al) Measurements with polarized filter H and D isotopic components and their fitting by Gaussian shapes po D s-D po H l, Å Left– spectra observed ; Right - H-alpha components p (red), polarization ┴ Bt; s (blue ), polarization ║ Bt. s+D sдет, отн. ед. po D po Н l, Å p component shape of H-alpha line fitted by two Gaussian functions.

Thomson scattering (lines of sights)- P-7 wavelength (1. 007 A) is very close to laser signal

Calculation method • Stambulchik E. , Maron Y. J. Phys. B: At. Mol. Opt. Phys. , 2008, 41, 095703 - Static Stark profiles • P. Fassbinder, W. Schweizer. Hydrogen atom in very strong magnetic and electric fields, Phys. Rev. A, v. 53, N 4 (1996) p. 2135 -2139 Zeeman shifts • Ion dynamics - FFM • Comparison: C. Stehle and R. Hutcheon, Astron. Astrophys. , Suppl. Ser. 140, 93 (1999).

Stark FWHM of H 10 and P 10 lines (Stambulchik E. , Maron Y. J. . , 2008 vs C. Stehle and R. Hutcheon, 1999 )

Density and Temperature distribution in ITER divertor V. Kotov, D. Reiter, A. S. Kukushkin. Numerical study of the ITER divertor plasma with B-2 -EIRENE code package. Preprint Julich-4257, 2007

P-7 line shape across magnetic field (V. S. Lisitsa, E. E. Mukhin, M. D. Kadomtsev et al. Plasma Phys. Reports, 2012, v. 38, p. 157 -167). 1 – static Stark shape with Zeeman; 2 (red) –ion dynamics -FFM; 3 – electron impact; 4 – total shape with Dopler; Zeeman splitting is shown.

P-7 line shape along line of sight with continuum contribution along chord N 21

P-7 line shape along chord N 5

Nitrogen impurities spectral lines • Neutral N radiative transitions in the spectral range close to laser signal: • 10105, 13 – 10114, 64 Ǻ ( line 10112, 48 from NIST data) • Problem : line shapes of the corresponding transitions

Nitrogen impurities spectral lines (intensity distribution along observation chord- ADAS code) LINE Shapes?

Charge Exchange Recombination Spectroscopy • H(100 ke. V)+C+6=H++C+5(n=8)= C+5(n. Z=7)+hw 8 -7; • Doppler line shape = ion temperature Ti • • PROBLEMS: Cascade population: H(100 ke. V)+D+(Ti)= H++D(n); D(n)+C+6= C+5(n. Z=4 n)+ D+= C+5(4 n-8)+ hw= C+5(n. Z=7)+hw 8 -7

Selective (n, l) cx cross section H(n=1)+C+6=H++C+5(n, l)

Selective in nl charge exchange cross sections of H 0 beam with energy 100 ke. V on С 6+ ions С 6+ + H 0(n = 2) = С 5+(n. Z, l. Z) + H+ n. Z max≈ 8 n. Z max K. R. Cornelius, K. Wojtkowski, R. E. Olson. J. Phys. B, 33 (2000) 2017 -2035

HALO EFFECT - contribution of excited (n=2 -6) H atomic states • H(n)+C+6=H++C+5(n. Z=4 n) • Kcx=n 410 -8 cm 3 s-1 • C+5(n. Z=4 n)= C+5(n. Z=8)+hwn. Z-8= C+5(n. Z=7)+hw 8 -7

Scheme of the ITER CXRS equipment testing at T-10 Light collecting system of the CXRS at the T-10 System of registration of CXRS spectra DINA - 6 E 0 = 30 ke. V j(a. L) ≈ 8 m. A/cm 2 d 0=7 cm N= 10 pulses tpulse= 1 ms Tper= 40 ms Rotating shutter High Etendue Spectrometer Collecting optics EMCCD Photon. MAX 512 B Transmitting optics Optical fibres Mainly for CXRS lines Dα and Hα beam measurements Systems of holding of optical fibres Observation chords are placed with 5 cm step Spatial resolution is 3. 5 – 4. 5 cm HES spectrometer - prototype of a spectrometer for the CXRS diagnostics of ITER - is the basic element of the registration system: - F-number ≈ 3; - Slit height Нslit=30 mm; - Dispersion D=3÷ 5 Å/mm; - Transmission К=30 %; - Astigmatism ~10 μm; - Spectral resolution 0. 15 Å;

Examples of results

Experimental CXRS data from T-10 tokamak (V. Krupin, V. Tugarinov et al. )- sharp increase with Ne ?

Conclusion • 1. Interrelationship between SOL and divertor line shapes of Balmer lines: conditions for SOL spectra observations; • 2. Isotope contents from Balmer spectral line shapes – inverse problem solution; • 3. Background for Thomson scattering (Hisotopes + impurities + tungsten W? ) • 4. Contribution of excited HALO atoms to CXRS signal.