World ST Research - The FIRE Place · RRC Kurchatov Inst TRINITI KBSI KAIST ENEA, ... Image simulation of the expected ... 10/11-12/05 Status of World ST Research

FPA Meeting, 10/11-12/05 Status of World ST Research

Status of World Spherical Torus ResearchMartin Peng

NSTX Program DirectorORNL@PPPL

Fusion Power Associates Annual Meeting and Symposium:Fusion and Energy Policy

October 11-12, 2005, Washington, DC

Supported by Office ofScience

College W&MColorado Sch MinesColumbia UComp-XGeneral AtomicsINELJohns Hopkins ULANLLLNLLodestarMITNova PhotonicsNew York UOld Dominion UORNLPPPLPSIPrinceton USNLThink Tank, Inc.UC DavisUC IrvineUCLAUCSDU ColoradoU MarylandU RochesterU WashingtonU Wisconsin

Culham Sci CtrU St. Andrews

York UChubu UFukui U

Hiroshima UHyogo UKyoto U

Kyushu UKyushu Tokai U

NIFSNiigata UU Tokyo

JAERIHebrew UIoffe Inst

RRC Kurchatov InstTRINITI

KBSIKAIST

ENEA, FrascatiCEA, Cadarache

IPP, JülichIPP, Garching

ASCR, Czech RepU Quebec


World Spherical Torus Research Is Expanding – 22 “Concept Exploration” and “Proof of Principle” Experiments


World Spherical Torus Research Is Addressing Important Issues in Fusion

• Active collaboration• “Concept Exploration” STs• “Proof of Principle” STs• Contributions in world fusion programs


World Spherical Torus Research Has a Tradition of Strong Collaboration

• Active bilateral exchanges– UK-US on NSTX and MAST – START collaboration in 1997– Japan-US on STs – active exchanges since 2000;

contributed to formation of All-Japan ST Program in 2004– RF-US on NSTX and Globus-M – since 1997– Brazil-US on initiation of ETE – collaboration since 2000

• Annual International ST Workshop since 1994; IAEA TM on ST since 1999

• Special international journal issues on progress of ST research– IEEJ jounral issue to appear in November– NF issue under preparation

• Progressing toward more coordination in research


CDX-U Have Carried out Liquid Lithium Tray Limiter Experiments

• Argon glow discharge cleaning and tray heating removed surface coatings

• Lithium remains in tray with currents to ground ≈100A at Bp≈0.1T for ≈10ms

Liquid lithium in tray after ~40 discharges. Liquid lithium

in tray limiter

• 34 cm major radius, 10 cm wide, 0.64 cm deep

• Two halves with toroidal break• Heaters for Tmax ≈500oC


Impurity Control with Liquid Lithium Indicated by Reduction of Oxygen Emission

Plasma Current (kA)

OII

Em

issi

on (

arb.

uni

ts)

With Lithium

No Lithium

Many conditioning shots required without Li to achieve currents ≈ 60kA

No conditioning shots required with Li to achieve currents > 60kA


Pegasus Is an Innovative ST to Explore Plasma Limits as A → 1

Pegasus (US)


Pegasus Is Exploring Innovative Startup via Electron Beam Injection


LATE (J)



10

0

1

R (m)

a (m)

NSTX/MAST

LATE

QUESTAdvanced Fusion Research Center

TST-2 / TS-3/4“QUEST”

QUEST : Q-shu University Experiment on Steady State Spherical Tokamak


1 0-3

1 0-2

1 0-1

10 0

10 1

1 0-2 10 -1 1 00 10 1 1 02 103 10 4 1 05

BDFH

Ip(M

A)

T im e(s)

L A T E

T S T -2T R A IM -1M

N S T X

Research Region of QUEST

Time (s)

LATE

TST-2

NSTX / MAST

Proposed Device

Proposed Device

- 7 -

TST-2(Japan)

LATE(Japan)



Higher β,Higher fBS,

More compact

Longer pulse,steady state

CS-less op.

RF current drive

Comm. reactor

Very high β& steady state

NSTXMAST

UTST

QUEST

TS-3/TS-4

HIST, TST-2. LATE

Develop broader options for economical fusion reactor

Phase IIITarget

Strategy of the All-Japan ST Research Program(Prof. Yuichi Takase, June 2005)

Broad research utilizing all resources(existing ST, new ST at Kyushu, diagnostics,theory/modelling, reactor design, etc.)


Direct Measurement ofElectron Turbulence

Tangential scattering UCD

New Capabilities in NSTX

EF/RWM coils to extend β limits

Columbia

Novel j(r) diagnostics for Advanced physics

New PF1A coil for advanced shaping


0.9 1.0 1.1 1.2 1.3Major radius (m)

0.0

0.5

1.0

1.5

2.0

Tem

pera

ture

(keV

)

0

100

200

300

Toro

idal

vel

ocity

(km

/s)

Te

Ti

Vφ

#12546

0.9 1.0 1.1 1.2 1.3Major radius (m)

0.0

0.5

1.0

1.5

2.0

Tem

pera

ture

(keV

)

0

100

200

300

Toro

idal

vel

ocity

(km

/s)

Te

Ti

Vφ

#13035

L-mode H-mode

Ip ~750 kABT ~0.6T<ne> ~3x1019m-3

Ip ~750 kABT ~0.6T<ne> ~3x1019m-3

Spectrometer coupled to 224 chords64 toroidal chords on each NBI32 passive toroidal chords 64 poloidal chords (32 32 on/off-beam)

being commissioned

Enhanced CXRS (ΔR~ρLi) in MAST


χe ~ χi around mid-radius & close to χiZ-CH [Chang & Hinton]

H-mode Transport Coefficients Can Be Close to Ion Neoclassical

TRANSP modelling

Ti

Te

x1019

m-3

ne


STs Are Studying Super-Alfvénic Ion Heating for ITER and CTF

• NSTX has Super-Alfvénic ions (NBI), as in ITER (fusion α’s)

• Measured instabilities driven by such fast ions & coincidental fast ion losses

• Interactions driven by small ρfast* (ITER), copious fast ions (both), and Doppler shifted resonance with Alfvén instabilities (both)

• Will fusion α’s in ITER & CTF suffer similar losses?

0

1

2

3

4

5

6

/V Alfv始

0.0 0.2 0.4 0.6

CTF

ARIES-ST

NSTXITER

Supe

r-A

lfvén

ic

Central Fast Ion Pressure Fraction

Nor

mal

ized

Fas

t Ion

Spe

ed

Alfvén Mode Frequencies (kHz)

Energetic Neutral Particle Signal

NSTX 117541

Time (s)

Energy (keV)

Ln(fl

ux/E

0.5 )

(1/s

ter c

m2

eV1.

5s)

[E Fredrickson, S Medley]


Start-up Schemes – Double-Null Merging

compatible with future ST design

Double-null merging (DNM) involves breakdown at a quadrupole nullbetween pairs of poloidal coils in upper and lower divertor

Modelling predicts merging of plasma rings as current in coils ramped to zero

t=60ms Ip = 600 kA

t=15ms Ip = 150 kA t=21ms Ip = 250 kA t=45ms Ip = 450 kA

t=75ms Ip = 600 kA


After some optimisation, plasma current up to 340kA formed and plasma sustained for 0.3sec with zero current in central solenoid

Te ~ 0.5keV and ne ~ 9x1019m-3

Double-Null Merging Formation Demonstrated


HIT-II (US)


NSTX Produced Sustained ST Plasmas via Coaxial HelicityInjection (Introduced by HIT-II)

Univ. of Hiroshima camera: N. Nishino; R. Kaita

6.2ms

8.0

9.8

11.6

12.4

13.3

15.1

16.9

• Rapid turn-off of injector current → closure of plasma surface → 60 kA, ~2 m2 volume

• First demonstrated on HIT-II (U Wash)• Important progress for attractive ST and

Tokamak fusion systems

Injector

ClosedPlasmaSurface

Plasma Current (kA/10)

Injector Current (kA)

Injector Voltage (kV*10)


ELM Spatial Structure (Experiment + Theory)

Image simulation of the expected structure with q95=4 and n=10

Filaments are consistent with the structures expected from the theory of the non-linear evolution of ballooning modes [Wilson and Cowley]


Unique ST Properties and Approaches Advance Boundary Physics

Turbulence imaging: large ρislow dynamics enable good

resolution

ITER-relevant heat fluxes (10 MW/m2).

Shaping & flux expansion

0

2

4

6

8

10

12

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1

Heat Flux [MW/m 2]

Radius [m]

InboardDivertorTarget

OutboardDivertorTarget

CHI Gap

4.9 MW

4.1 MW

#109063: 4.9 NBI#109053: 4.1 MW#109034: 2.0 MW (all H-mode)

2 MW

Heat, particle fluxes: Detached regimes, lithium coatings & liquid targets

ELITE (GA)ORNL, DIII-D

Pedestal stability: strong shaping, low A: magnetic geometry pedestal

stability & SOL transport

Dα

H97L

NSTX


NSTX Accesses High β, High Bootstrap Plasmas

CTF

NSTX⇒ Toroidal Physics (ITER)

⇒ Component Test Facility (CTF)⇒ Power Plant

Fusion RequiresHigh Beta

Steady State

CTF


• Improved divertor coils• Extended plasma to stronger shapes• High triangularity at high elongation leads

to quiescent core and edge conditions

Substantially Expanded the Spherical Torus Operating Space to Clarify Future ST Options

Tria

ngul

arity

Vertical Elongation

StrongerShapes

Energy Replacement Times

Nor

mal

ized

Per

form

ance

(βNH

89P)

2002-2003

20052004

[D Gates]

[J Menard]Demo

CTF


On-axis, counter-PINI

Jackable on/off-axis co-PINI

Double box: 2× co-PINIson- and off-axis

Investigating bold options for NBI current profile control

Flexible system 4 PINIs, up to 10 MW (1 counter- and 3 co-current)

Off-axis NBCD optimised with 2 off-axis co- and 2 on-axis co/counter PINIs

MAST Upgrades: Proposed NBI Systems


BUTTRESSES ⇒ Reduce Risk/Acceleration(Sir. Chris Llewellyn Smith, FPA meeting 2005)

Multi-beam material test facility - study damage from irradiation with heavy ions to material samples with implanted Helium ( + hydrogen?) Satellite tokamak - to be operated in parallel with ITER, as part of ITER programme, to test new modes of operation, plasma technologies,...Component Test Facility (CTF) - to test engineering structures (joints, …) in neutron fluences typical of fusion power stations

We assume that a ‘fast track CTF’ (possibly a small spherical tokamak that would not need to breed tritium?) could be operating with D-T in 2026

Assuming successful development, it would speed up the advent of fusion power significantly and reduce risks (note that in ‘Pillars only’ model DEMO phase 1 is effectively a very expensive and large CTF)


ST Research Contributes to Major Components of Office of Science 20-Year Strategic Plan for Fusion

ComponentTest Facility

PerformanceExtension Test

ITER PerformanceEnhancement


World Spherical Torus Research Is Expanding and Addressing Important Issues in Fusion

• Growing in breadth and depth – 22 experiments in active collaboration

• “Concept Exploration” STs push the ST scientific envelope– Explore high leverage innovations– Establish basis for “Proof of Principle” testing

• “Proof of Principle” STs– Contribute to resolve issues important to ITER burning

plasma performance– Establish scientific feasibility for ST “performance

extension,” CTF volume neutron source, & Demo Optimization

• STs are part of plans in world fusion programs

World ST Research - The FIRE Place · RRC Kurchatov Inst TRINITI KBSI KAIST ENEA, ... Image simulation of the expected ... 10/11-12/05 Status of World ST Research

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