Active Beam Spectroscopy in Hot Fusion Plasmas (Introduction) Seminar-I Institute for Plasma Physics Academy of Sciences Hefei, China May, 5, 2007 Acknowledgement: CXRS groups at JET, TEXTOR, Tore Supra, ASDEX-UG and members of the ITPA expert group on Active Beam Spectroscopy Manfred von Hellermann FOM Institute for Plasma Physics Rijnhuizen, NL

M. von Hellermann 1)Introduction to Active Beam Spectroscopy 2)Spectral Analysis, Evaluation and Simulation Codes 3)Beam Emission Spectroscopy and MSE

M. von Hellermann Outline  Basic concepts of active beam spectroscopy (CXRS + BES)  CXRS on JET  Global Consistency Checks based on CXRS  CXRS and BES on ITER making use of a DNB

M. von Hellermann CXRS Aims : 1) Helium ash measurement 2) Impurity ion densities 3) Fuel mixture and density 4) Plasma rotation 5) Ion temperature 6) Particle transport studies BES & MSE Aims : 1) Localisation of active volume 2) Local Beam Density (BES) 3) Density Fluctuations(BES) 4) Local pitch angle (MSE) 5) Local Lorentz field (MSE)

M. von Hellermann Active Beam Spectroscopy ( basic principles)  localized measurement  quantitative use of intensities  intrinsic consistency of temperature, rotation and density  advanced collisional radiative atomic modelling  beam emission spectroscopy as indispensable collateral to CXRS  BES and MSE

M. von Hellermann Courtesy: Carine Giroud

M. von Hellermann Beam Emission Spectroscopy on TEXTOR D-CXRS

M. von Hellermann Combination of CXRS and BES: common line of sight and beam geometry Beam Emission Spectroscopy as tool for absolute calibration of CXRS signals

M. von Hellermann local concentration measurements reduced to a line ratio measurement Combination of CXRS and BES enables deduction of ion densities without absolute calibration and measurement of optical transmission Combination of CXRS and BES enables deduction of ion densities without absolute calibration and measurement of optical transmission Note: Atomic rates Q depend on energy, electron and ion densities and temperatures

M. von Hellermann Ion Temperature, Velocity and Density measurement Ion Temperarure deduced from Doppler width. Velocity can be deduced from Doppler shift Density can be deduced from measured intensity can be deduced from continuum background Ti v Reference line For global consistency all physics parameters extracted simultaneously from CX spectrum including its baseline need to be validated

M. von Hellermann Variation of the cross-section with beam energy D 0 +He 2+ -> D + + He + (n=4 -> n=3) D 0 +Be 4+ -> D + + Be 3+ (n=6 -> n=5) D 0 +C 6+ -> D + + C 5+ (n=8 -> n=7) Intensity of Charge-exchange emission Effective CX emission Rates provided by ADAS

Core CXRS diagnostic at JET Spatial resolution: limited by l.o.s. intersection of flux surfaces in beam volume Time resolution: limited by detector readout ~50ms. Courtesy: Carine Giroud

M. von Hellermann Parasitic emission to active charge-exchange emission Parasitic emission: electron impact and passive CX emission of other species coming from the edge of the plasma. C 2+ electron impact Be 1+ electron impact C 5+ charge-exchange spectra

M. von Hellermann Parasitic emission: passive charge-exchange with thermal deuterium neutrals Parasitic emission to active charge-exchange emission Line of sight Neutral beam Zone of high passive charge-exchange C 5+ active CX C 5+ passive CX Top view of torus

M. von Hellermann Some JET CXRS results

M. von Hellermann Example of the use of Charge Exchange measurements Internal transport barrier#51976 Courtesy: Carine Giroud

M. von Hellermann Example of the use of Charge Exchange measurements Impurity transport studies Crucial to study impurity behaviour Low and high Z impurity: fuel dilution (He ash) High Z : radiative collapse Courtesy: Carine Giroud

M. von Hellermann CHEAP Charge Exchange Analysis Package  Mapping of physics quantities on symmetrised coordinates (magnetic flux surface indices)  Monitoring of main low-Z ions including bulk ions  Self consistent calculation of beam-target interaction processes  Primary data consistency checks (effective ion charge, kinetic plasma energy, neutron yield

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Z eff contributions from C +6, Ar +16 and Ar +18 JET pulse #61388

M. von Hellermann Z eff -Visible Bremsstrahlung (Abel inverted) Z eff reconstructed from C +6, Ar +16 and Ar +18

M. von Hellermann Reconstruction of Thermal and Beam -Thermal Neutron yield in DT plasma

Chris Walker, ITER CT Diagnostic beam for ITER: E=100keV/amu, P=3.6MW, div=10mrad, distance to blanket opening 19.2m

M. von Hellermann Table II 200 keV, 50 A D beam Source Dimensions : Y = 1.53 m (high) and X =0.58 m Divergence of the main beam : 10 mrad  I II III  ’ (mrad)  ’ (mra d)  (mra d)  (mr ad) Y’( m) X’( m) Current (A)Power at observatio n point (MW) Launched power (MW) Fractional power transmitt ed Halo component (15% main beam Divergence (85% main beam) Aperture dimensio ns Ape rtur e loca tion (m) Fy (m) Fx (m) Case Courtesy: Drs M.Singh, S.Mattoo, Institute for Plasma Research, India

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Conceptual optics design for ITER Core-CXRS U-port periscope combining neutron labyrinth and Cassegrain output optics full view of DNB path (2m) Double Vacuum Window Adjustment mechanism Rear of periscope Fibres to spectrometers Cassegrain output to fibres

M. von Hellermann Optics layer Step 4 Placing of upper shielding blocks Connection blocks to cooling system Shielding block TNO periscope design: “Central Removable Tube” containing First-Mirror and Shutter Friso Klinkhamer, TNO

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Proposed active (focussed on DNB) and passive (off-beam) fibre bundles

M. von Hellermann TRINITI Spectrometer ITER CXRS proto-type spectrometer developed by TRINITI, Troitsk, RF Echelle 15 th order, F/3, f=500mm, 0.25nm/mm

M. von Hellermann Littrow spectro + Pixelvision ccd TRINITI spectro + Pixis 400B ccd # A same line of sight Red: during NBI Blue: before NBI

M. von Hellermann ParameterRangeTime ResSpace resaccuracy Vtor1-200 km/s10 msa/3030% Vpol1-50 km/s10 msa/3030% Ti, core (r/a<0.9) keV100 msa/1010% Ti, edge (r/a>0.9) 50eV-10 keV 100 msTbd10% Core He density 1-10%100 msa/1010% ITER CXRS measurement requirement table

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Simulated Continuum level, fluctuation and HeII signal strength for ITER U-port 2 (left) and U-port-3 (right) U-port-3 continuum level is slightly below U-port-2 level due to shorter path length through plasma

Error Analysis for CVI, U-port-2,  =100ms

Error Analysis for simulated HeII spectra, ITER Upper-port-2,  =100ms, Doppler width and shift deduced from simultaneously analysed CVI

           D-alpha-edge D-alpha-CX   DNB induced MSE and CXRS spectrum, B=5.3T, E=100keV/amu

M. von Hellermann MSE and CXRS on D error analysis

M. von Hellermann Summary remarks  Active Beam Spectroscopy offers a rich diagnostic potential for present and future fusion experiments  Substantial progress has been achieved in a quantitative analysis of active spectra and results are considered as indispensable input for plasma interpretation codes  Advanced atomic modelling and self consistent analysis procedures have led to a general acceptance of CXRS as a reliable diagnostic and plasma control tool  Future fusion devices as ITER do envisage the use of CXRS with challenging demands on components and beam sources