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A Joint Australian Fusion Energy Initiative

A Joint Australian Fusion Energy Initiative. Strategic plan for Fusion Science – ITER forum Capability, infrastructure, Flagship Diagnostic? Initial ISL projects – Howard $0.5M, Hole et al $0.4M Next Step ? Clean Energy Fund? $3M Govt, $3M others Expertise:

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A Joint Australian Fusion Energy Initiative

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  1. A Joint Australian Fusion Energy Initiative • Strategic plan for Fusion Science – ITER forum • Capability, infrastructure, Flagship Diagnostic? • Initial ISL projects – Howard $0.5M, Hole et al $0.4M • Next Step ? Clean Energy Fund? $3M Govt, $3M others Expertise: • plasma diagnostics: typically spectroscopy and laser (ANU, Syd, Macq) • Exotic and high temperature materials (ANSTO, Unew,Syd, ANU….) • peculiar plasma shapes (heliac) • Theory • Divertors and plasma walls! couple with “unclaimed” ITER diagnostic subsystems

  2. Flaked-off deposited films and dust: JET Divertor Pumping slots 8 1 7 3 4 6 Tile 4 J.P. Coad, 1998

  3. There are 2 LASER based depth probing techniques (LASER radar1 & Speckle interferometry2) which meet ITER requirements if a 2-wavelength system is used. • Measure net effect of erosion and deposition • No Tokamak tested prototype, however, LASER radar used off-line on TFTR • need reference point to distinguish erosion from vessel/divertor displacement • from dome, target strike zones are visible (change in divertor profile) 1) Erosion Measurement system [1] K Itami et al [2] P. Dore et al Dore P and Gauthier E 2006 Speckle interferometry: a diagnostic for erosion-redeposition measurements in fusion devices 17th Int. Conf. on Plasma Surface Interaction in Controlled Fusion Devices (Hefei, China, 22–6 May 2006)

  4. AUSTRALIA Wider Australian fusion-relevant capabilities • Atomic and molecular physics modeling • High heat flux alloys • MAX alloys synthesis • Materials characterisation • Quasi-toroidal pulsed cathodic arc • Plasma theory/ diagnostics • Dusty Plasmas The University of Sydney • Plasma spectroscopy • MHD and kinetic theory • Materials science analysis Faculty of Engineering • joining and material properties under high heat flux • High temperature materials • Manages OPAL research reactor Australian Nuclear Science &Tec. Org.

  5. MAX alloys are one promising route : M = transition metal (Sc, Ti, V, Cr, Zr, Nb, Mo, Hf, Ta) A = Al, Si, P, S, Ga, Ge, As, Cd, In, Sn, Tl, Pb X = either C or N Different Stochiometries  over 600 potential alloys. Spectroscopy lab The first wall of a fusion reactor has to cope with the ‘environment from hell’ so it needs a ‘heaven sent surface’. A sample of Material Science research in Australian Universities – Newcastle Univ.also University of Sydney, Melbourne • heat load of 10-100 MW m-2 • 14 MeV neutron irradiation • 10 keV D, T, He bombardment • Good thermal, electrical conductor • high melting point • ideally composed of low Z specie • not retain too much hydrogen • high resistance to thermal shocks

  6. Finite-b equilibria in H-1NF S. Lloyd (ANU PhD) , H. Gardner EnhancedHINT code of late T. Hayashi, NIFS Vacuum b = 2% b = 1% Island phase reversal: self-healing occurs between 1 and 2% b

  7. Different  in each region MRXMHD: Multiple relaxation region model for 3D plasma equilibrium Motivation: In 3D, ideal MHD (A) magnetic islands form on rational flux surfaces, destroying flux surface (B) equilibria have current singularities if p  0 Present Approach: ignore islands (eg. VMEC ), or adapt magnetic grid to try to compensate (PIES). Latter cannot rigorously solve ideal MHD – error usually manifest as a lack of convergence. ANU/Princeton project: To ensure a mathematically well-defined J, we set p = 0 over finite regions  B = B,  = const (Beltrami field)separated by assumed invariant tori.

  8. Prof. I. Bray: Curtin University Presentation to IAEA 2009

  9. Atomic Cross-Sections for ITER World-leading calculation of atomic cross-sections relevant to fusion using their “Convergent Close Coupling” (CCC) Method Recent study of U91+, Li, B3+ and Tungsten (W73+) for ITER

  10. IEC: Doppler spectroscopy in H2: Predicting experimental fusion rates J. Kipritidis & J. Khachan 12

  11. Results: sample Hα spectrum at the anode wall (Summed H2+, H3+) This peak used for prediction 13

  12. Densities of fast H2.5+at the cathode aperture are ~ 1-10 x 1014 m-3 Results: neutron counts! (constant voltage) PhysRevE 2009 Dissociation fractions ffastat apertures are ~ 10-6(increases with current!) Slope=1 line Supports neutral on neutral theory: Shrier, Khachan, PoP 2006 14 (Summed H2+, H3+)

  13. Levitation of Different Sizes Particles - Samarian Bulk Plasma Sub-micron particles Sub-micron dust cloud Sheath Edge 2.00 micrometer dust 3.04 micrometer dust 3.87 micrometer dust 4.89 micrometer dust Levitation Height 6.76 micrometer dust Powered Electrode RF Sheath Diagnostic • Probing of sheath electric field on different heights

  14. Dust Deflection in IEC Fusion Device – Samarian/Khachan IEC Diagnostic IEC ring electrodes (cathode) Phys Letts A 2007 • Dust particle being deflected towards the rings are visible on the left hand side

  15. ANU - University of Sydney collaboration Brian James Daniel Andruczyk • Development of a He pulsed diagnostics beam • Te profiles measured in H-1NF, from He line intensity ratios, with aid of collisional radiative model John Howard Scott Collis Robert Dall

  16. Experimental set-up

  17. Collection optics Pulsed He source Skimmer Pulsed Valve

  18. Spectral line emissivity vs radius Tevs radius beam emissivity falls as beam moves into the plasma due to progressive ionization

  19. ResearchExamples from H-1 • Effect of Magnetic Islands on Plasma • Alfven Eigenmodes in H-1

  20. ResearchExamples from H-1 • Effect of Magnetic Islands on Plasma • Alfven Eigenmodes in H-1

  21. H-1 Heliac: parameters

  22. H-1 configuration (shape) is very flexible • “flexible heliac” : helical winding, with helicity matching the plasma,  2:1 range of twist/turn • H-1NF can control 2 out of 3 oftransform () magnetic well and shear  (spatial rate of change) • Reversed Shear Advanced Tokamak mode of operation low shear  = 4/3  = 5/4 medium shear Blackwell, International Meeting on the Frontiers of Physics, Malaysia 2009 Edge Centre

  23. Santhosh Kumar Experimental confirmation of configurations Rotating wire array • 64 Mo wires (200um) • 90 - 1440 angles High accuracy (0.5mm) Moderate image quality Always available Excellent agreement with computation

  24. Mapping Magnetic Surfaces by E-Beam Tomography: Raw Data M=2 island pair For a toroidal helix, the sinogram looks very much like part of a vertical projection (top view) Sinogram of full surface

  25. Good match confirms island size, location computed + e-beam mapping (blue/white ) Good match between computed and measured surfaces • Accurate model developed to account for all iota (NF 2008) • Minimal plasma current in H-1 ensures islands are near vacuum position • Sensitive to shear identify sequence number  high shear surfaces “smear” Iota ~ 3/2 Iota ~ 1.4 (7/5)

  26. Effect of Magnetic Islands Giant island “flattish” density profile Possibly connected to core electron root enhanced confinement Central island – tends to peak Blackwell, International Meeting on the Frontiers of Physics, Malaysia 2009

  27. Spontaneous Appearance of Islands Iota just below 3/2 – sudden transition to bifurcated state Plasma is more symmetric than in quiescent case. Uncertainty as to current distribution (and therefore iota), but plausible that islands are generated at the axis. If we assume nested magnetic surfaces, then we have a clear positive Er at the core – similar to core electron root configuration? Many unanswered questions……Symmetry?How to define Er with two axes?

  28. Identification with Alfvén Eigenmodes: ne phase • Coherent mode near iota = 1.4, 26-60kHz, Alfvénic scaling with ne • Poloidal mode number (m) resolved by “bean” array of Mirnov coils to be 2 or 3. • VAlfvén = B/(o) B/ne • Scaling in ne in time (right) andover various discharges (below) 1/ne ne f 1/ne Critical issue in fusion reactors: VAlfvén ~ fusion alpha velocity fusion driven instability! Blackwell, International Meeting on the Frontiers of Physics, Malaysia 2009

  29. Fluctuation Spectra Data from Interferometer upgrade: (Rapid electronic wavelength sweep) Profiles Fluctuation spectra Turn-key Fast sweep <1ms D Oliver

  30. Alfven Mode Decomposition by SVD and Clustering • 4 Gigasamples of data • 128 times • 128 frequencies • 2C20 coil combinations • 100 shots • Initial decomposition by SVD  ~10-20 eigenvalues • Remove low coherence and low amplitude • Then group eigenvalues by spectral similarity into fluctuation structures • Reconstruct structuresto obtain phase difference at spectral maximum • Cluster structures according to phase differences (m numbers)  reduces to 7-9 clusters for an iota scan Grouping by SVD+clustering potentially more powerful than by mode number • Recognises mixturesof mode numbers caused by toroidal effects etc • Does not depend critically on knowledge of thecorrect magnetic theta coordinate increasing twist

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