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Fusion Research Facility: Overview and Upgrade Plans (is there potential to be an additional training platform in diagnostics and plasma physics for KSTAR?) B.D. Blackwell, J. Howard, D.G. Pretty, J.W. Read, H. Punzmann, J. Bertram, M.J. Hole, F. Detering, C.A. Nuhrenberg, M. McGann, R.L. Dewar, J. Photo: Martin Conway Australia-Korea Foundation mission to KSTAR, 2010

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The Australian Plasma Fusion Research Facility: Overview and Upgrade Plans (is there potential to be an additional training platform in diagnostics and plasma physics for KSTAR?). - PowerPoint PPT Presentation

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Page 1: Photo: Martin Conway

The Australian Plasma Fusion Research Facility: Overview and Upgrade Plans(is there potential to be an additional training platform in diagnostics and plasma physics for KSTAR?)

B.D. Blackwell, J. Howard, D.G. Pretty, J.W. Read, H. Punzmann, J. Bertram, M.J. Hole, F. Detering, C.A. Nuhrenberg, M. McGann, R.L. Dewar, J. Bertram Australian National University, and *Max Planck IPP Greifswald,

Photo: Martin Conway

Australia-Korea Foundation mission to KSTAR, 2010

Page 2: Photo: Martin Conway

The Australian Plasma Fusion Facility: Results and Upgrade Plans

IntroductionResult Overview: MHD Modes in H-1

Data miningAlfvénic ScalingOptical MeasurementsRadial Structure

Facility Upgrade Aims Key areas New diagnostics for Upgrade

Conclusions/Future

2

Page 3: Photo: Martin Conway

H-1NF: the Australian Plasma Fusion Research Facility

Originally a Major National Research Facility established by the Commonwealth of Australia and the Australian National

University

Mission:• Detailed understanding of the basic physics 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

MoU’s for collaboration with

Members of the IEA implementing agreement on development of stellarator concept.

National Institute of Fusion Science, Princeton Plasma Physics Lab

Australian Nuclear Science and Technology Organisation

3

Page 4: Photo: Martin Conway

H-1 CAD

4

Major radius 1mMinor radius 0.1-0.2mMagnetic Field 1 Tesla (0.2 DC) q 0.5 -1 (transform 1~2)

ne 1-3x1018

Te 20eV (helicon) <200eV (ECH) 0.01 - 0.1%

Page 5: Photo: Martin Conway

Blackwell, Australian ITER Workshop, 10/2006

H-1NF Photo

Page 6: Photo: Martin Conway

H-1 configuration (shape) is very flexible

6

• “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 andshear (spatial rate of change)

• Reversed Shear like Advanced Tokamak mode of operation

Edge Centre

low shear

medium shear

= 4/3

= 5/4

twis

t pe

r tu

rn (

tran

sfor

m)

Page 7: Photo: Martin Conway

Blackwell, Australian ITER Workshop, 10/2006

Large Device Physics on H-1Confinement Transitions,

Turbulence (Shats… 1996--)– H-mode 1996

– Zonal Flows 2001

– Spectral condensation of turbulence 2005

Magnetic Island Studies – H-1 has flexible, controlled and verified geometry

– Create islands in desired locations (shear, transform)

– Langmuir probes can map in detail

Alfvén Eigenmodes (next )

D3D tokamak H-1

Pinj (MW)

1

2

3

Edge ne (1019 m–3)10

Edge Te (keV)

0.1

0.2

0.3

1600 2000 2400 2800t (ms)

Edge Te (eV)

t (ms)

6

3

Prf (kW)

ne (r/a = 0.3) (1017 m–3)

80

40

0

030

20

10

20 40 60

Page 8: Photo: Martin Conway

Experimental confirmation of configurationsRotating wire array• 64 Mo wires (200um)• 90 - 1440 angles

High accuracy (0.5mm)Moderate image quality Always available

Excellent agreement with computation

T.A. Santhosh Kumar B.D.Blackwell, J.Howard

Santhosh Kumar

Iota ~ 1.4 (7/5)

Page 9: Photo: Martin Conway

Effect of Islands on Plasma• LHD, JT60U results show

– Te profile flattened – radial transport high

(inside side to outside side)– But this doesn’t mean that internal transport is high

(from the inside to the outside of the island.)– Internal rotational transform is quite low and can complicate experiments– 10 to 100 toroidal transits to circumnavigate island?

Conditions:

Argon plasma ~10eV

Te ~ 10 eV, Ti ~ 10 eV 30-80 eV∼

electron density 1 × 10∼ 18/m3

nn < neutral fill density 0.81 × ∼ 1018/m3

ρe 0.075 mm, ρ∼ i 35-55 mm∼

νei 9×10∼ 5/sec νen 1.6×10∼ 5/sec

Collision mean free path λei 2.5 m, λ∼ en 8 m∼

Santhosh Kumar

Page 10: Photo: Martin Conway

Small, core islands

Density peaked near island axis (O-point)

Potential negatively peaked there too.

Local symmetry about local magnetic axis, but apparently not globally (axis to axis)

Blackwell, Kyoto JOB 16th March 2009

B AC

Page 11: Photo: Martin Conway

Unanswered QuestionsIssues Remaining:

What is the correct analysis for Er?When does the plasma “see/not see” islands”

collisionality, i, e internal transform are important

What is the most robust indicator of surface number?

(p? – varies with ne by a fraction of Te (Boltzmann relation))

“Correct” analysis for Er?If we take the axis at the core core electron rootIf we assume two axes, then ion root, but field is

still large (characteristic of e-root)[Conditions for usual e-root picture (1/, trapped e) not met]

Page 12: Photo: Martin Conway

MHD/Mirnov fluctuations in H-1

Blackwell, ISHW Princeton 2009 13

David Pretty

Page 13: Photo: Martin Conway

Identification of Alfvén Eigenmodes: ne• Coherent mode near iota = 1.4, 26-60kHz,

Alfvénic scaling with ne• m number 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)

phase

1/ne

ne

f 1/ne

Critical issue in fusion reactors:

D + T He + n

VAlfvén ~ fusion alpha velocity fusion driven instability!

Page 14: Photo: Martin Conway

Blackwell, KSTAR2010

Identification with Alfvén eigenmodes: k||, iota

Why is f so low? - VAlfven~ 5x106 m/s

res = k|| VA = (m/R0)( - n/m) B/(o)

• k|| varies as the angle between magnetic field lines and the wave vector

k|| - n/m

• iota resonant means k||, 0

Expect Fres to scale with iota

ota (twist)

= 4/3

Resonant

Page 15: Photo: Martin Conway

Mode structure via synchronous 2D imaging• Intensified Princeton Instruments camera synchronised with mode

• Light imaged for various delays

• Averaging/Accumulation is performed by the camera

16

Toroidal Field Coils

HelicalConductor

John Howard, Jesse Read

Page 16: Photo: Martin Conway

Alfvén Eigenmode structure in H-1Compare cylindrical mode with optical emission

measurementsTest functions for development of a Bayesian

method to fit CAS3D modes to experiment.

John Howard, Jason Bertram, Matthew Hole

Page 17: Photo: Martin Conway

First Results from Gas Puff Imaging - true 2D imaging

• Intensified Princeton Instruments camera synchronised with mode

• Select a small range of toroidal angles with a gas puff (Neon)

• Intensity ~ ne

• Initial results 2D image without assumptions of rotation, mode number.

18

John Howard, Jesse Read

Mirnov Array 1

Mirnov Array 2

Interferometer

RF Antenna

Viewline

Gas Puff

Page 18: Photo: Martin Conway

Third Mirnov Array (Toroidal)

New Toroidal ArrayCoils inside a SS thin-wall bellows (LP, E-static shield)

Access to otherwise inaccessible region with•largest signals and •with significant variation in toroidal curvature.

Shaun Haskey

Mirnov Array 1Mirnov Array 220 pickup coils

Interferometer

RF Antenna

0.2m

Page 19: Photo: Martin Conway

Australian Plasma Fusion Research Facility Upgrade

2009 Australian Budget Papers

• Australian Government’s “Super Science Package”

• Boosted National Collaborative Infrastructure Program using the “Educational Infrastructure Fund”

$7M, over 4 years for infrastructure upgrades (no additional funding for research)

Page 20: Photo: Martin Conway

Aims of Facility Upgrade

Consolidate Facility infrastructure including that required to implement the Australian ITER Forum strategy plan

Aim to involve the full spectrum of the ITER Forum activities

More specifically:• Improve plasma production/reliability/cleanliness

– RF production/heating, ECH heating, baking, gettering, discharge cleaning

• Improve diagnostics– Dedicated density interferometers and selected spectral monitors

permanently in operation

• Increasing opportunities for collaboration– Ideas?

• Increasing suitability as a testbed for ITER diagnostics– Access to Divertor – like geometry, island divertor geometry

Page 21: Photo: Martin Conway

RF Upgrade

RF (7MHz) will be the “workhorse”– Low temperature, density limited by power– Required to initiate electron cyclotron plasmaNew system doubles power: 2x100kW systems.New movable shielded antenna to complement “bare” antenna

(water and gas cooled).Advantages:– (non resonant – Helicon) Very wide range of magnetic fields in Argon – (ion-cyclotron resonant) New system allows magnetic field scan while

keeping the resonant layer position constant.e.g. to test Alfven scaling MHD

Additional ECH source (10/30kW 14/28GHz) for higher Te

Page 22: Photo: Martin Conway

Improved Impurity Control

Impurities limit plasma temperature (C, O, Fe, Cu)High temperature (>~100eV) desirable to excite spectral lines

relevant to edge plasma and divertors in larger devices.

Strategy : Combine - • Glow discharge cleaning for bulk of tank• Pulsed RF discharge cleaning for

plasma facing components.• antenna (cooled) and source (2.4GHz)

• Low temperature (90C) baking • Gettering – Titanium or Boron (o-carborane)

Access Island Divertor Geometry

Ashley Gibson

“Island Divertor”

Page 23: Photo: Martin Conway

Small Linear Satellite Device – Plasma Wall Interaction Diagnostics

Purpose:Testing various plasma wall interaction diagnostic conceptse.g. Doppler spectroscopy, laser interferometry

coherence imaging, imaging erosion monitor

Features:Much higher power density than H-1 H-1 cleanliness not compromised by material erosion diagnostic testsSimple geometry, good for shorter-term students, simpler projectsShares heating and magnet supplies from H-1

Magnetic Mirror/Helicon chamber

Mirror coils

Optical Diagnostics

Heliconsource

ne ~ 1019 m-3

P ~ 1MW/m2

Page 24: Photo: Martin Conway

Helicon H+ source ConceptBased on ANU, ORNL work

Quartz/ceramic tubem=+1 Helicon AntennaDirectional

Gas Flow

• Helicon Antenna is an efficient plasma source in Ar• High Density (>1018 m-3) more difficult in H• Combination of higher power and non-uniform

magnetic field has produced ne ~ 1019 m-3in H

Water cooled target

Mirror Coils

ne ~ 1019 m-3

(Mirror coils at one end should be sufficient – mainly to provide field gradient rather than full mirror effect.)

Page 25: Photo: Martin Conway

Additional Power/Plasma Sources

Sheath acceleration increases power density, but if >30-50V physical sputtering

(not normal in fusion simulators, but may be useful to increase erosion?)

E-beam can increase dissipation, but ion bombardment damage of LaB6 cathode if pressure too high?Solid LaB6 Cathode, >10A emission

Sterling Scientific washer gun H+ 1019-1020

5-15eVunder the right conditions, can generatea relatively clean plasma (low W)den Hartog: Plasma Sources Sci. Technol. 6 (1997) 492–498.

(also useful for a simple way of obtainingfirst plasma)

15mm

Page 26: Photo: Martin Conway

Future

Research • New Toroidal Mirnov Array • Bayesian MHD Mode Analysis• Toroidal visible light imaging (Neon)• Correlation of multiple visible light, Mirnov and n~

e data• Spatial and Hybrid Spatial/Temporal Coherence Imaging

Facility upgrade• Develop divertor and edge diagnostics• Study stellarator divertors, baffles

e.g. 6/5 island divertor• Develop “plasma wall interaction” diagnostics • Linear “Satellite” device for materials diagnostic development

multiple plasma sources, approach ITER edge

Blackwell, H1 Results & Upgrade, AKF_KSTAR 2010

Page 27: Photo: Martin Conway

H-1NF is an excellent toroidal graduate student machine – complements Korean facilities

• Large device physics accessible – MHD/Alfvénic modes.– Island studies

• Very good diagnostic access – Invites imaging and multiview interferometric diagnostics

• Precise control of magnetic geometry, q (0.5 1) and shear.• High repetition rate, availability

– 0.5 Tesla : 200 shots/day (hydrogen/helium/deuterium)– Low field student mode : 500 shots/day (argon, Langmuir probes etc.)

• Complementary high density hydrogen linear machine (~1019)– Simpler geometry– Edge plasma density and power density approaching ITER (over a small area)– fast diagnostic/vacuum “turnaround” time

• MDSPlus/JavaScope data common between KSTAR/H-1NF/MDFBlackwell, H1 Results & Upgrade, AKF_KSTAR 2010