Dense Plasma Focus : small inexpensive device

E. J. Lerner, Chief Scientist, LPPFusion, Inc.Nov 12, 2014

Focus Fusion: the Fast Route to Fusion Energy Systems

University of the SouthLPPFUSION

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What Would HappenIf We had Cheap Clean Energy?

What if we could develop in the next five years a 5 MW energy source 10 times cheaper than any now available that was safe and non-polluting?

Economic Benefits

17% increase in real income for median industrialized country resident44% increase in real income for median person in the world

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JOBS, Services and Infrastructure$5 TRILLION per year not spent on energy100-150 million new jobs globally

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Environmental Benefits

End 7 million deaths per year from pollution by coal, diesel, gasolineEnd oil spills, mining devastationTotal recycling with plasma torchMoney released to end deforestation, environmental clean-upNo greenhouse gasesNo radioactive waste

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Benefits for Peace

No more war to prop up the price of oilFission energy is obsoletelock up the uranium mines

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Distributed Power

5 MW generators, safe enough to put in neighborhoods far more reliability in disasters, rapid deployment to towns and villages throughout the world

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ITER TOKAMAK

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Dense Plasma Focus : small inexpensive device

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FOCUS FUSION 1, Experimental Device

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Focus-Fusion-1 Experimental Device12-CAPACITOR BANK

Stored energy 100kJ (vs 10 GJ for JET) Capacitor potential 45 kVPeak current 1.4-2.8 MA

Electrodes: 5 cm cathode, 2.8 cm anode

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How could we possibly be so small and fast?

Magnetic fields supplied by currents not external magnets2) Use natural instabilities, not fight them3) Seeking metastability, not absolute stabilityfar easier

Physics of the DPFParallel Currents Attract :Pinch Effect

Ampere and the Pinch Effect http://vimeo.com/97608819

Key ConceptsHow Do We Know the Magnetic Field?Amperes LawHow Do We Know the Force?Lorentz Force Law

Physics of the DPFAmperes lawAmpere-1826Maxwell1864Heaviside 1884-89The curl of the magnetic field at any point is proportional to and in the same direction as the rate of change of the electric field with time plus the current density (current per area).

Meaning of the curl

Imagine the magnetic field as a flow of fluid in the direction of the magnetic field at every point. Then If your fingers of the right hand are in the direction of the flow then your thumb defines the axis the fluid is spinning the direction of the curl and the rate of spin is the magnitude of the curl. The current density gives the curl of the field and the curl lets us calculate the magnetic field

Lorentz Force LawHeaviside 1889Lorentz 1892F=q(E + vXB)

Force on a charge is equal to the charge q times the sum of the electric field strength and the cross product of the particles velocity and the magnetic field strength

How A DPF Device Works

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Magnetic Field of DPF

Unpinch, Rundown, Pinch

Force-Free Vortex Filaments1950-1963

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Key plasma parameters-- such as velocity--are scale-invariant

In Lab: 10 cm , msecSolar flare: 10,000 km, 100 secGalaxy: 30 kpc, 15 MySuper-cluster: 100 Mpc, 100Gy

The Cosmic ConnectionAlfven, Falthammar

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Spiral Galaxy

Quasars

Beam From Star FormationREPRODUCING NATURAL INSTABILITIES

Solar Flares

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PLASMOID

8ns after pinch

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Metastability Far EasierHigh Density, High B field ITER DPFMinor radius cm 200 6x10-4Ion velocity 108cm/s 1.2 10

B Field 5x104 5x109 Ion density 1014 1024Confinement time 400 s 6 nsIon revolutions 4x107 1.6x10325,000 times easier

What Is Aneutronic Fusion? Its a fusion using aneutronic fuel, ideally made of hydrogen and boron, pB11, which produces no neutrons and thus no radioactive waste.Aneutronic No neutrons No Radioactive waste

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Faradays Law

Faraday 1831The curl of the field is proportional to and in the opposite direction from the rate of change of the magnetic field with time.

ENERGY CAPTURE DEVICEX-rays, Ion Beams

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SAFENO neutrons from main reactionNO high energy neutronsNO radioactive wasteelectrodes contain less radioactivity than a roomful of people.Generator safe to service without protection 9 hours after turn-off

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How Safe?0.8 micro curies of radioactivity in each used set of electrodes.Radioactivity of human child about 0.2 micro curiesRadioactivity of classroom of 25 children5 micro curiesNO RADIOACTIVE WASTE

Aneutronic DPF Allows Far Higher Energy Density, Far Lower Cost ITER Focus FusionPower (MW) 500 5Power/m3 0.05 1200Power/m2 0.5 40Neutron power/m2 0.5 0.08

Fusion ComparisonFusion Yield/Energy InputEnergy output per 1,000 J inputDT: DD:JET 2.2 J 0.01 JSarov DPF 0.2 J 0.00045 JNIF 0.03 JFF-1 DPF 0.004 J

Where Are We?

Ion temperature goal achieved over 1.8 billion degrees, enough to ignite pB11

Confinement time goal achieved 20 nsmore than 8 ns goal

Energy transfer to plasmoidover 50% of goal

Densitymust increase by 10,000

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Steps To Increase Density

50x-- Achieve theoretical densitytungsten electrodes to eliminate impurity

10x-- Increase current to 2.8 MA

20x-- Better compression with heavier pB11

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How Do we Reduce X-ray Cooling?

X-ray emission increases as z2Boron 25 x as emissive as hydrogenHow do we avoid this?

Reducing X-ray CoolingQuantum Magnetic Field Effect

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Quantum Magnetic Field Effect2003

QMEF reduces Te by >20xCuts X-ray by >4xAllows ignition of pB11BUT only with B>~3 GG

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Ion energy of 160 keV

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Generated Interest

How Does it Get so Hot?Main Mechanism is Viscous HeatingHaines, others

Ordered Motion Into Random Motion

Higher Densities, Electron Beam Wave Heating

Why Does DPF Fusion Yield Plateau?LPPHYSICS.COM

Sources of Impurities: Erosion of Anode, Arcing at JoinsAmounts: 0.6mg from anode erosion, 0.4mg from arcing 50% of D sheath massLPPFUSION

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LPPHYSICS.COMImpurities as CauseUneven impurity distribution(2012)asymmetric sheathpoor compressionIncrease in collision rate with zeff4(2013)prevents magnetization of filamentsleading to double sheathLow DensityYield Plateau

What We Should See

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What We Actually See

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New-2014Cause of Anode Erosion: Runaway Electrons

(PHYSICS OF PLASMAS 21, 102706)During breakdown, with high E fields

Vre=5.5e(E/40p)^1/2 eV

(Tarasenko and Yakovlenko)

Vaporization occurs if thermal conduction cant carry away heat at the boiling point

e(E/40p)^1/2 eV> 0.22LwT(rEtC/t) 1/2/I

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Why More Effect with Higher Current?

1) Arcing above 2 MA/cm2

2) Magnetization of filaments easier to disrupt Magnetization depends on B/n. For B2/n constant, B/n declines with increasing B

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Monolithic Electrodes Connected Outside Chamber

Solution to Arcing

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Getting the B FieldFF-1Now 0.06 GGWith filaments0.6 GGFull current1.3 GGWith pB1110 GG

Needed: Beryllium electrodes

Tungsten is fine for impurity, but absorbs too many x-raysBeryllium far more transparentBut costs-- (single unit)--$120,000

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Biggest Engineering ChallengesHeat RemovalElectrode ErosionSputtering may limit electrode lifetime but with re-deposition a few weeks may be OKAnode will be heated by x-rays- key upper limiting factor in repetition rateDeposition of boron- key lower limit on repetition rate

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Why Has it Taken So Long?Massive Underfunding:

Tungsten too expensive

Too few large experiments

Under staffing slows progress

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