Recent Results from the H1 National Facility

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Recent Results from the H-1 National Facility
Boyd Blackwell , M. Hole, J. Howard, D.G. Pretty,
J.H. Harris, S.M. Collis, D. Andruczyk, B.W.
James, F.J. Glass, T.A. Santhosh Kumar, M.G.
Shats, C.A. Michael, H. Punzmann, G.G. Borg H-1
National FacilityAustralian National University
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H-1NF National Plasma Fusion Research Facility

• Established in 1997 by the Commonwealth of
  Australia and the Australian National University
• 12/2005 Contract signed to extend operation to
  2010 and fund operational costs from the existing
  grant.
• The Board is being re-constituted to encourage
  development of collaborative proposals covering a
  broader range of areas (e.g. advanced energy,
  fusion science and technology and materials).
• Mission
• Detailed understanding of the behaviour of
  magnetically confined hot plasma in the HELIAC
  configuration
• Development of advanced plasma measurement
  systems
• Fundamental studies including turbulence and
  transport in plasma
• Contribute to global research effort, maintain
  Australian presence in the field of plasma fusion
  power
• The facility is available to Australian
  researchers through the AINSE1 and
  internationally through collaboration with Plasma
  Research Laboratory, ANU.
• 1) Australian Institute of Nuclear Science and
  Engineering

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H-1 Heliac Parameters

• 3 period heliac 1992
• Major radius 1m
• Minor radius 0.1-0.2m
• Vacuum chamber 33m2 excellent access
• Aspect ratio 5 toroidal
• Magnetic Field ?1 Tesla (0.2 DC)
• Heating Power 0.2MW 28 GHz ECH 0.3MW 6-25MHz
  ICH
• Parameters achieved to dateexpected
• n 3e18 1e19
• T 100eV(Te)500eV(Te)
• ? 0.1 0.5

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E-Beam mapping (wire tomography)
B.D.Blackwell, J. Harris, T.A. Santhosh Kumar,
J.Howard

• Rotating wire array
• 64 Mo wires (200um)
• 90 - 1440 angles
• High accuracy (0.5mm)
• Moderate image quality
• Always available
• Tomography Challenges
• Asymmetric resolution
• Undersampled in impact radius
• only 64 wires, unlimited data in ?
• Somewhat perturbative
• Collected current on one wire steals from
  another

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E-Beam Tomography Raw Data
M2 island pair
For a toroidal helix, the sinogram looks very
much like part of a vertical projection (top view)
Sinogram of full surface
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E-Beam mapping

• Good match between computed and measured
  surfaces
• Sensitive to shear ? identify sequence
  number ? high shear surfaces smear

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H-1 Remote control/Automatic scans

• Four PLCS

Cooling, vacuum and sequence control Generator
and heating power control
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Poloidal mode number measurements
phase
Expected for m 2
magnitude

• bean-shaped 20 coil Mirnov array
• Phase vs poloidal angle is not simple
• Boozer coords
• External to plasma
• Propagation effects
• Large amplitude variation
• Phase problem reduced at higher m, amplitude
  problem worsens.
• Significant interpretation problem in advanced
  confinement configurations

Coil number
Coil number
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Identification with Alfvén Eigenmodes
phase

• Coherent mode near iota 1.4, 26-30kHz, Alfvénic
  scaling with ne
• m number resolved by bean array of Mirnov coils
  to be 2 or 3.
• Cylindrical theory predicts two possible GAEs at
  m2, and m3
• Resolve by analysing data from second bean to get
  both an independent value of m, and an estimate
  of N (in progress).
• Many other examples of Alfvénic scaling

Two possible GAEs 20-25kHz
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Planned Exploration of EPM Physics
(also with M. J. Hole, L. C. Appel)

• Passive Alfvén eigenmodes Synergistic
  theory/experiment study of wave drive, and effect
  on confinement.
• Experiment Multiple sources of non-thermal
  particle populations RF heating, ECH, molecular
  beam and gas puff.

• Diagnosis. Essential for EPM studies. Some
  include
• ne tomographic interferometer. (10kHz, 2cm
  resol.)
• Ti,vi coherence imaging optical system
• ?Bext 2 x 20 coil Mirnov arrays ? (m,n) up
  to 200 kHz
• ?Bext CAE measurements, flt 5MHz OMAHA coils
  (UKAEA)
• ?Bint sensitive mm-wave homodyne
  polarimeter/interferometer.

200 kW, 28GHz gyrotron

• Active Excitation
• Compressional Alfvén antenna 100s kW.
• Selective frequency tuning for electron or ions
  (4-26 MHz)

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Multiple Fluid Modelling
(M. J. Hole, G. Dennis)

• Multiple different energetic populations present
• H-1 thermal ions, electrons, injected cold fuel
  ions, energetic ions/electrons driven by
  wave-particle resonance heating, and runaway
  electrons,
• MAST energetic ions produced (indirectly) via
  injected neutral beams,
• ITER fusion-born ?s

• Distribution functions will be modelled by a
  combination of functional parameterisation and/or
  numerical simulation.

• Moments of the distribution functions ? Multiple
  fluid model

• Preliminary Working Extension of PPPL/ Univ. of
  Rochester code FLOW to handle multiple Maxwellian
  populations.

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Data Mining handles large quantities of data
D. Pretty

• 4 Gigasamples of data
• 128 times
• 128 frequencies
• 2C20 coil combinations
• 100 shots
• Data mining allows sub sampling, exploring and
  rule extraction
• Initial work with Weka java and Gabor
  transforms for time freq analysis
• Huge data sets are a common problem in complex
  geometries often associated with advanced
  confinement configurations

D. Pretty
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Mode Decomposition by SVD and Clustering
D. Pretty

• 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

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Mode Decomposition by SVD and Clustering
D. Pretty

• 4 Gigasamples of data
• 128 times
• 128 frequencies
• 2C20 coil combinations
• 100 shots
• .
• Cluster structures according to phase differences
  (m numbers)
• ? reduces to 7-9 clusters for an iota scan
• Grouping by clustering potentially more powerful
  than by mode number
• Recognises mixtures of mode numbers caused by
  toroidal effects etc
• Does not depend critically on knowledge of the
  correct magnetic theta coordinate

m0,3,5
m3,1
m3
m2
m0
m1
m1,2,3
m4
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Alfvén resonant frequencies overlaid on Clusters
E and F
D. Pretty
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Helium Diagnostic Beam
The University of Sydney

• Purpose to locally measure Te and ne (Sasaki et
  al.)
• Very narrow (15mm) very brief (200us) burst of He
• 1019 atoms /m3
• tiny increase in base pressure
• Allows point localised measurements

Skimmer Pulsed jet
D. Andruczyk, S. Collis
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Helium Diagnostic Beam - results

• Very narrow (15mm) very brief (200us) burst of He
• 1019 atoms /m3
• tiny increase in base pressure
• Allows point localised measurements
• Fires every 2 msec
• ? time evolving radial profiles (Sasaki et al.)
• Example shows ECH collapse in dirty plasma
• For plasma gt 100eV, results not so clear at
  present

Background increase due to impurity Si
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Recent Results (2005)

• Configurational effects demonstrated
• particle confinement effects, magnetic fluct.
  spectra
• Poloidal mode numbers identification with Mirnov
  array, Toroidal soon
• Alfvénic modes observed
• Datamining unsupervised reduction of 40 probes
  in 100 configurations into physically significant
  clusters
• New campaign of surface and magnetic island
  mapping to provide insight into configuration
  scan
• Fast scanning density interferometer profile in
  lt 2 ms (Alfven, islands)
• Tomographic emission and temperature imaging
  demonstrated
• Possible without assumption of magnetic surfaces,
  kHz time resolution
• Ion temperature via 4 frame phase-split
  interferometric imaging
• Two supersonic directional gas jets for fuelling
  and imaging diagnostics operational
• Multi Point measurements of Te via He line ratio,
  multi-pulse
• Engineering improvements
• Extensive remote control of operation ? computer
  scans, automatic logging
• ECH magnet current controlled by PLC to /-
  0.5Amp, Bolometer in W/G

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Future

• Dynamics - modulation of n and T, gas puffing
• possibility of high field confinement transitions
  with increased power
• New diagnostics
• Second Soft Xray array with interchangeable foil
  (University of Canberra)
• Triple probe array (T3)
• LIF E-field measurements
• Heating RF and ECH higher power, higher
  temperature
• 200kW ECH, 250kW RF, improved discharge cleaning
• Progression to high temperature e.g.
• Turbulence/Flow studies via correlation
  spectroscopy, microwave scattering
• Radial force balance information via MOSS
  spectroscopy
• Extensive Configuration Studies
• three control windings ? iota, well and shear
• higher power for stability studies approaching ?
  0.5
• interchange, ballooning modes.