Collective Ion Acceleration Mechanism with Petawatt

Collective Ion Acceleration Mechanism with Petawatt-Subpicoseocond Laser Pulses Heinrich Hora1, Paraskevas Lalousis2 ... Dielectric response by refrac...

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Collective Ion Acceleration Mechanism with PetawattSubpicoseocond Laser Pulses Heinrich Hora1, Paraskevas Lalousis2 & Stavros Moustaizis3 1University

of New South Wales, Sydney/Australia 2Institute of Electronics and Laser FORTH, Heraklion, Crete,Greece 3TechnicalUniversity of Crete, Chania, Greece

Nuclear Fusion Energy Deuterium-Tritium reaction (DT) 4

D + T = n + He + 17.6 MeV Reaction of Protons with Boron-11 (HB11) 1

H +

11

4

B = 3 He + 8.67 MeV

(less radioactivity per energy than from burning coal)

Thermonuclear Burn

Nanosecond: THERMAL COMPRESSION & IGNITION (NIF) for DT

HB11: 100.000 times more difficult than DT

Essential change with PW-ps

Only 5-times more difficult?

Plasma block acceleration by PW-ps pulse

ULTRAHIGH ACCELERATION Plasma hydrodynamics (1978...) Particle dynamics (PIC)

Force density and dielectric change

in Maxwell’s stress tensor f = -p + fNL fNL = [EE + HH - 0.5(E2 + H2)1 + (1+(/t)/w)(n2-1)EE]/(4p) - (/t)E x H/(4pc) Nonnlinear Force acts instantly with nearly 100% efficiency to convert optical laser energy into machenical energy of the electron cloud where the inertia is given by the attached ion cloud Dielectric response by refractive index n is essential

Nonlinear Force in plane geometry (along x) fNL = -(∂/∂x)(E2 + H2)/8p = (1–n2)(∂/∂x)(Evac2/n) Refractive index n2 = 1 – (ne/nec)/(1–in/w) dielectric modified and HF-extension of static ponderomotive force Z. Naturforsch. 22A, 278 (1967; Phys. Fluids 12, 181 (1969); Phys. Fluids 28, 3706 (1985); Phys. Rev. E 85, 036404 (1912)

Numerical results: plane geometry, Bi-Rayleigh initial density, Intensity 1018W/cm21978: ACCEL. OF DEUTERIUM IN 2 ps:

>1020 cm/s2

VERY FIRST MEASUREMENT OF PLANE GEOMETRY NONLINEAR FORCE ACCELERATION: 2×1020cm/s2 FROM DOPPLER SHIFT

R. SAUERBREY, Phys. Plasma 3, 4712 (1996) Using TW laser pulses of 0.35 ps duration, contrast ratio 108. Essential: suppression of

prepulse. No relativistic Self-focusing

New Effect: clean laser pulses

Intensity dependence of the velocity of the plasma front from the Doppler shift of the reflected 700fs KrF laser pulses from Aluminium target (Földes, Szatmari et al., 2000).

Ultrahigh acceleration 2x1019 cm/s2

Generation of directed plasma neutral with ULTRAHIGH

j >

12 10

blocks, space charge

ION CURRENT density 2 Amps/cm

H. Hora, J. Badziak et al. Phys. Plasmas 14, 072701 (2007); H. Hora Laser and Particle Beams 27, 207 (2009)

Sheath Acceleration: PIC computation of separate electron & ion cloude behind target (Labaune et al Nature Comm. 2013)

Bobin-Chu side-on picosecond ignition of solid density DT (1972-74): impossibly high 8 2 energy flux threshold: E*>10 J/cm

After ultrahigh acceleration of plasma blocks (1978; 1996) based on nonthermal conversion of laser energy into macroscopic motion by nonlinear force: Picosecond

initiation of fusion flame

Ion density depending on the depth x of the propagating fusion flame at same times as in Fig. 1. 3x109 W/cm3

Spherical irradiation on DT for avoiding lateral energy losses .

Threshold of Energy Flux using collective electron stopping power (Hora, Malekynia et al. Appl.Phys.Lett 93 011101 (2008))

E* = 2×107Joule/cm2 for DT, = 108 for HB11 (Opt.Commun. 282, 4124 (2009)) If including ion stopping by secondary avalanche alpha interaction:

Increase of HB11 Fusion gain German Patent Appl. 102013013140.5. non-classified: 8.8.2013

ICAN spherical fibre laser (polymers) Fibre ends 1 on sphere of radius R with radial fibre axes for producing ps spherically converging laser pulse interacting with sphere 3 of HB11 fuel for initiating a fusion flame

ICAN inner diameter 2 meters, HB11 fuel diameter 0.56mm, spherical laser pulse of Exawatt/1ps produces 69 MJ fusion energy electrostatically converted by nearly 100% into electric energy Laser and Particle Beams Vol.31 published 9 Nov. 2013 First view Articles (H. Hora et al.) DOI: 10.1017/S0263034613000876

What to be done: - Spherical ICAN with low cost polymer fibers for Exawatt (>1024 W/cm2). - Study Ultrahigh plasma block acceleration and ultrahigh ion density beams for target interaction especially at short time.

- Shock mechanism including ion beam pellet fusion

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