Richard E. Siemon- Atlas for magneto-inertial fusion

8/3/2019 Richard E. Siemon- Atlas for magneto-inertial fusion

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Atlas for magneto-inertial fusion

Richard E. Siemon

6th Symposium

CURRENT TRENDS IN INTERNATIONAL

FUSION RESEARCH: A REVIEW

7-11 March 2005,

Washington, DC, U.S.A.


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SynopsisMagnetized Target Fusion (MTF) is the approach to fusion energy that is intermediate inparameters between conventional magnetic and conventional inertial fusion. Typical

parameters are microsecond time scales, megabar pressures, megagauss magnetic field, andmegajoules of energy. The essential ingredients are formation of a plasma target containing thefusion fuel embedded in a magnetic field to improve energy confinement, followed by pulsedcompression of the fuel to achieve fusion reactions during the inertial dwell time of thecompression system. A variety of detailed approaches are being considered for this purpose.1-4

Theoretical analysis shows that the intermediate regime of parameters has better prospects for

economical development of practical fusion energy than either extreme represented byconventional approaches.5

This year the Atlas pulsed power facility, designed and developed at Los Alamos NationalLaboratory, is beginning to operate at the Nevada Test Site. It is the worlds largestmicrosecond pulsed power system. Given that the primary purpose of Atlas is high-energy-density science for stockpile stewardship, it is serendipitous that Atlas is also extremely well

suited for critical tests of the magneto-inertial fusion concept.The design of an initial experiment on Atlas will be described that investigates magnetic fluxcompression without plasma, and generation of magnetic field in the megagauss regime.6 Annew and interesting aspect of the experiment is a unique method of providing seed flux forcompression by diverting a small amount of current from the main Atlas power system while itdrives a liner implosion.

Progress on formation of an MTF plasma target has been recently reported by Los Alamosresearchers,7 and other possibilities are being investigated.8 Plans for a campaign of Atlasexperiments based on this progress are being developed. This campaign is one part of aroadmap for developing the MTF concept, which was recently prepared by the internationalcommunity of scientists interested in MTF. The roadmap shows how Atlas in combinationwith other existing pulsed power facilities can provide a faster pathway to fusion than possiblewith conventional approaches.


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References

1. D.D. Ryutov and R.E. Siemon, Comments on Modern Physics 2, 185 (2001).2. Y.C.F. Thio, C.E. Knapp, R.C. Kirkpatrick, R.E. Siemon, and P.J. Turchi, J. Fusion Energy

20, 1 (2001).

3. F. Winterberg, Phys. Plasmas 11, 706 (2004).

4. A.J. Kemp, M.M. Basko, and J. Meyer-ter-Vehn, Nucl. Fusion 43, 16 (2003).

5. R.E. Siemon, P.J. Turchi, D.C. Barnes, J.H. Degnan, P. Parks, D.D. Ryutov, F.Y. Thio, Proc.12th International Toki Conference, Toki, Japan (2001).

6. T.S. Goodrich, R.E. Siemon, B.S. Bauer, T.E. Cowan, I.R. Lindemuth, V. Makhin, R. Faehl,R. E. Reinovsky, 46th Annual Meeting of the Division of Plasma Physics, Savannah, Georgia,Nov. 15-19, 2004

7. G. A. Wurden, T. P. Intrator, S. Y. Zhang, I. G. Furno, S. C. Hsu, J. Y. Park, R. Kirkpatrick,

R. M. Renneke, K. F. Schoenberg, M. J. Taccetti, M. G. Tuszewski, W. J. Waganaar, ZhehuiWang, R. E. Siemon, J. H. Degnan, D. G. Gale, C. Grabowski, E. L. Ruden, W. Sommars, M.H. Frese, S. Coffey, G. Craddock, S. D. Frese, N. F. Roderick, Paper IC/P6-53, Proc. 20thIAEA Fusion Energy Conference, Vilamoura, Portugal (2004)

8. R.E. Siemon, W.L. Atchison, B.S. Bauer, A.M. Buyko, V.K. Chernyshev, T.E. Cowan, J.H.Degnan, R.J. Faehl, S. Fuelling, S.F. Garanin, A.V. Ivanovsky, I.R. Lindemuth, V. Makhin,

V.N. Mokhov, R.E. Reinovsky, D.D. Ryutov, D.W. Scudder, T. Taylor, V.B. Yakubov, PaperIC/P6-48, Proc. 20th IAEA Fusion Energy Conference, Vilamoura, Portugal (2004).


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Terminology

Magneto-inertial fusion (MIF) is the general idea of achieving fusion with ahigh-density pulsed system that incorporates magnetic field

--magnetic field to improve energy confinement during burn

--high-energy-density achieved with high-power pulsed technology

--time scale governed by inertia of material surrounding the heated fuel

Magnetized Target Fusion (MTF) is the subset of MIF approaches that seeks

to work at a density intermediate between conventional inertial and magnetic

systems.

--preheat the fuel and compress to thermonuclear temperature with one of

several possible pushers.

--metal liners and pulsed systems like Atlas are available now to test basic

concept


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FRC plasma target


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DT Fuel Mass heated to10 keV

103

Required DT Fuel Mass

Density (gram/cm3

)

1

10-3

10-6

10-9 10-6 10-3 1

FuelMass(grams)

Diffusion-limitZero magneticfield

NIF

ApproximateUpper-limit Bohm

Advancedconcepts

ITER

Diffusion-limitclassical magnetic confinement

MTF

FuelE

nergy(joule

s)

106

109

103

MTF regime is intermediate between MFE and ICF


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Intrinsic fusion cost considering size andpower is minimized around 1 Mbar

10

100

1000

10000

1.E+02 1.E+04 1.E+06 1.E+08 1.E+10 1.E+12

ITER-FEAT

FIRE

NIF

Z

Atlas

Generic MTF

Nominal tokamak

High pressure tokamak

Fuel pressure (megabar)

0.0001 .01 1 100 10000

Facilitycost($M

)

10

100

1000

10000

1.E+02 1.E+04 1.E+06 1.E+08 1.E+10 1.E+12

ITER-FEAT

FIRE

NIF

Z

Atlas

Generic MTF

Nominal tokamak

High pressure tokamak

Fuel pressure (megabar)

0.0001 .01 1 100 10000

Facilitycost($M

)

See Siemon et al.,

Toki conference (2001).


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MIF can be developed faster thanconventional fusion

Road map analysis suggests a time scale of 20

years instead of 50 yearsCost of development is reduced because

facilities are intrinsically less expensive.


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Concept ExplorationPlasma target experiments & Liner tests

Theory & Modeling

~ $5 M/year

Proof-of-Principle

Atlas facility / Variety of targets~$20M/y

Performance Extension

Atlas & Engineering Prototypes

$30-50M/y

Energy Development

Demo$1B

Commercialization

Power plant$2B

2015

NASA Development

Ground-based rocket$1B

Manned Exploration

of Solar System

Stockpile Stewardship

Intense neutron source$300M

20122012

Integrated plasma-on-liner test

T~1 KeV, Qeff~0.01

Economic feasibility

demonstrated

Engineering & Economics

demonstrated

PoP experiment

Qeff~1

Mission adopted

Rocket-specific

technology

demonstrated

Technology,

Materials,Theory,Ad

vancedComputing

R

ampingto~$10M/yatProof-of-Principle~$2

5M/yatPerformanceE

xtension

Magneto-inertial Fusion Roadmap

Design based on

mission requirements

Spac e Energy Defense

20252025

2010

2007

Concept ExplorationPlasma target experiments & Liner tests

Theory & Modeling

~ $5 M/year

Proof-of-Principle

Atlas facility / Variety of targets~$20M/y

Performance Extension

Atlas & Engineering Prototypes

$30-50M/y

Energy Development

Demo$1B

Commercialization

Power plant$2B

20152015

NASA Development

Ground-based rocket$1B

Manned Exploration

of Solar System

Stockpile Stewardship

Intense neutron source$300M

20122012

Integrated plasma-on-liner test

T~1 KeV, Qeff~0.01

Economic feasibility

demonstrated

Engineering & Economics

demonstrated

PoP experiment

Qeff~1

Mission adopted

Rocket-specific

technology

demonstrated

Technology,

Materials,Theory,Ad

vancedComputing

R

ampingto~$10M/yatProof-of-Principle~$2

5M/yatPerformanceE

xtension

Magneto-inertial Fusion Roadmap

Design based on

mission requirements

Spac e Energy Defense

2025202520252025

20102010

20072007

Roadmap


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Atlas power supply

Standard person

240 kV

24 MJ~ 25 nH30 MA


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Atlas is ideal for doing importantMTF experiments

Near term -- magnetic flux compression to

megaguass field level in an MTF-relevant

geometry

Longer term using various plasma targets,

test plasma compression inside a liner


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Flux compression experiment isbeing designed

z

Atlas Bank Current

Conductinghard core

5cm

5mm

Insulator

Metal

Liner

Shunt

z

Atlas Bank Current

Conductinghard core

5cm

5mm

Insulator

MetalMetal

Liner

Shunt


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Liner implosion with trapped fluxresults in megagauss magnetic field

Magnetic Field and Radius vs Time

0102030

4050607080

90100

0 5 10 15

Time(s)

Radius(mm)

B-500(T)

B-200(T)


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Hard-core stabilized z pinch ispotential MTF target plasma

B

Plasma

current

Hard core

current

B

Plasma

current

Hard core

currentPlasma

Outer conductoris the imploding liner


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MAGO generates hard-corestabilized z pinch

MAGO at VNIIEF

I. R. Lindemuth, et al., Magnetic

Compression / Magnetized Target Fusion

(MAGO/MTF): A Marriage of Inertial

and Magnetic Confinement, 16th IAEAFusion Energy Conference, Montreal,

Canada, October 7-11, 1996.


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Self-organization indiffuse z pinch

Plasma is unstable if pressure gradient violates Kadomtsevcriterion

Result is turbulent interchange motions of flux tubes in the rzplane (B=B).

Plasma fluctuates in space and time around the marginalKadomtsev-stable pressure profile.

Process observed in numerical simulations of many different

initial conditions; consistent with MAGO experimental data. Process illustrated by simulation using idealized initial

conditions with eg. pressure gradient 10% too large

See Makhin et al., Physics of Plasmas, April 2005


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Sequence of interchange motionfollowing Q=1.1 initial profile

Z(m

)

Plasma density contours (color) and velocity streamlines

R(m)t = 1.0 s t = 2.0 s


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Last moment of interchange before chaotic mixing;Mass contours and velocity stream lines


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Chaotic mixture after interchange;

mass contours and velocity stream lines


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Diffuse z pinch target on Atlas

z

Atlas Bank Current

Hard core

5cm

5mm

Coaxial Plasma Injector

Insulator

Metal

Liner

Switch

z

Atlas Bank Current

Hard core

5cm

5mm

Coaxial Plasma Injector

Insulator

MetalMetal

LinerLiner

SwitchSwitch

Plasma injector and Atlas Bank

are separate electrical circuits

Coaxial injector could be aMAGO device or a Marshall

Gun type accelerator

Liner region labeled switchcauses the plasma injection gap

to close at the beginning of liner

compression

After switching action plasmawith flux is trapped in a

toroidal chamber surrounding

the hard core, and

compressional heating occurs as

the liner implodes.


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Liner driven by Atlas(Raven 1D code)

-10

0

10

20

30

40

50

60

0 5 10 15 20 25 30

Liner outsideLiner inside

Current

Hard core

R

adius(mm);Current(MA)

Time (s)

-10

0

10

20

30

40

50

60

0 5 10 15 20 25 30

Liner outsideLiner inside

Current

Hard core

R

adius(mm);Current(MA)

Time (s)

0

0.1

0.2

0.3

3.5 4 4.5 5

Radius (mm)

Tempera

ture(eV)

Boil

Melt

20 s

21 s

19 s

0

0.1

0.2

0.3

3.5 4 4.5 5

Radius (mm)

Tempera

ture(eV)

Boil

Melt

20 s

21 s

19 s

Initial liner 50-mm radius,

10-cm long, 2-mm thick

Surface of hard core reaches

boiling temperature just beforetime of maximum compression


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2D MHRDR simulation results

18 20 22 24 260

20

R(mm)

18 20 22 24 26-5

0

5

V

km/s

18 20 22 24 260

5

10

/1024(m-3)

18 20 22 24 260

5

(s)

(keV)

VelocityLiner inner radius

Hard-core radius

t(s)

18 20 22 24 260

20

R(mm)

18 20 22 24 26-5

0

5

V

km/s

18 20 22 24 260

5

10

/1024(m-3)

18 20 22 24 260

5

(s)

(keV)

VelocityLiner inner radius

Hard-core radius

t(s)

--compressible two-fluid model

--Braginskii coefficients of thermalconduction and electrical resistivity.

--Ohms law is E+vxB= j-- No Hall terms or thermoelectric termssuch as Nernst current included.

Neutrons ~ 4x1012

Excellent diagnostic

See Siemon et al., NuclearFusion, to be published (2005).


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Compressed plasma turbulentstructure

time= 2.290e-005s

5.2 5.4 5.6 5.8 6 6.2

x 10-3

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

500

1000

1500

2000

2500

3000

3500

4000

5.5 6 6.5

x 10-3

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

time= 2.290e-005s

9.2

9.4

9.6

9.8

10

10.2

Temperature contours& white streamlines

Pressure contours


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Issues that need study

Modeling of plasma formation process by MAGO or othercoaxial generators is needed.

Transport modeling should include estimates for Bohmmicroturbulence, wall-plasma interaction, sheath physics, andradiation from impurities.

A coating of lithium on walls (optionally including dissolvedhydrogen fuel) offers the possibility of low-Z contamination.

Future simulations should examine radiation from a lithium-hydrogen plasma mixture.

Hall terms and thermoelectric terms such as Nernst current

(not in simulation) need further investigation.

RS, VM, BSB 5/26/03


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MTF Team

HyperV Technologies

U. Wisconsin

U. Colorado

U. Washington

UNR

UNLV

NTSLLNL

UCDavis

GA

LANL

AFRLNASA

MSFC

Groups funded (often small) or proposing to work on MTF


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Summary

An exciting possibility to advance fusion with MTF on Atlaspresents itself.

Results from MTF exploratory experiments on Atlas andShiva Star in the next two years will motivate a larger MTFProof-of-Principle campaign on Atlas.

International team is in place to do this work.

Proposed plan has small impact upon other DP plans and

resources; valuable method for recruiting DP manpower.

The moment is right for a significant MTF initiative

Documents

Richard E. Siemon- Atlas for magneto-inertial fusion