J.limpouch-Plasma and High Energy Density Physics

8/4/2019 J.limpouch-Plasma and High Energy Density Physics

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Plasma and High Energy

Density Physics (RA5)

J. Limpouch

Czech Technical University in PragueFaculty of Nuclear Sciences and Physical Engineering

Bř ehová

7, 115 19 Prague 1, Czech Republic, [email protected]

ELI Beamlines ScientificChallenges Workshop



ELI Basic Distinctions

Focused intensities 10-1000× higher than present

• Fundamentally new physics will be investigated

• Relativistic ion oscillations in laser field

• Relativistic electron temperatures – thermal

bremsstrahlung → electron-positron pair creation• Isochoric heating of dense matter to keV temperatures

Synergy of laser and secondary sources

• Various combinations of laser pulses, x-ray sourcesand beams of accelerated particles will be usedfor plasma creation and diagnostics



Strong European community of researchers

vast experience in experimental, theoretical and numericalstudies of relativistic laser interactions with various targets

Long-time experience with large user facilitiesincluding lasers, target chambers and diagnostics

Range of methods for diagnosticsactive and passive optical, X-ray and particle methods

Prerequisites for success



RA5 – “Plasma and high energy densityphysics” – oriented to fundamental research

to acquire knowledge of studied systems and interactions ELI will be user facility

impossible to predict all future research directions, but the

compiled list of topics is meant as a guideline for interactionarea specification

Applications of results of RA5

• Optimization of secondary sources• Future laser technology• Novel fusion schemes

• Laboratory astrophysics• Technological applications (e.g. accelerator technol.)

Research activity 5



1. Nonlinear optics and laser interaction

with underdense plasmas2. Relativistic HED plasmas

3. Laser interactions with dense matter4. Interactions with clusters and MLT

5. Warm dense matter6. Testing of inertial fusion schemes (IFE)

Selected topics of research



The propagation of high-intensity, coherent,electromagnetic radiation in plasmas, and the

resulting modifications of the plasma state Wakefield formation behind laser pulse –

important for electron acceleration

1. NL optics of plasmas ..

Proton projection image taken 20 ps after interaction of 35 fs Ti:Sapphire laser pulse

of intensity 5×1019 W/cm2 with tenuous plasma of density ~ 1017 cm-3 formed in frontof 0.9-μm-thick mylar foil by laser prepulse. Small scale ~25-30 μm structures areclearly depicted (M. Borghesi et al., Phys. Rev.Lett. 94 (2005), 195003)



Coherent radiation can scatter from and decay intocollective plasma modes.It can create radiation at new frequencies. The plasma oscillations maybecome self-organized, nonlinear, kinetic. Simple modes can be stronglyinfluenced by nonlinear kinetic modes, such KEEN and KEIN waves.Relativistic electromagnetic solitons may be formed by fields trapped in

prolate cavities in electron density.


E B

The phase space of relativistic KEENwave in Vlasov simulations of stimulatedRaman scattering ( A. Ghizzo et al., Phys.

Rev. E 74 (2006), 046407 )

Isolated soliton andsoliton train afterlaser pulse (T. Esirke-

pov

et. al., Phys. Rev.

Lett. 89 (2002),275002)



Intense ultrashort laser pulses may be am-plified and compressed by seeded stimulated

Raman or Brillouin scatteringplasma tolerates much higher laser intensity than any othermedium


Experimental setup, seed (16 μJ) is amplified to

2.9 mJ by pump laser (82 mJ) and shortenedfrom 550 fs to 90 fs(J. Ren et al., Nature Physics 3 (2007), 732)



ELI beamlines facility will be capable of heatingplasma to relativistic temperatures ≥ 0.5 MeV

thermal bremsstrahlung photons have energy sufficient for creationof electron-positron pairs, plasma with positron density comparableto ion density will be created

2. Relativistic HED plasma

Diagram of pair creation.Electron colliding with high Z ion

emits γ

photon that collides with

another high Z ion and electron-positron pair is created

Electron and positron spectrum, when

1 ps pulse of intensity 1020 W/cm2 wasincident on thick golden target (H. Chen

et al., Phys. Rev. Lett. 12 (2009), 105001)



Complicated interaction of ELI with solid-density targetsradiation pressure ~ 10 Tbar and oscillating electron energy ~ 1 GeV

Laser absorption, relativistic transparency, channel boring and ionacceleration will be investigated.

Laser absorption - linear × circular polarizationlinearly polarized light is absorbed by fast electrons, while 2ω component ofponderomotive force is absent for circular polarization and laser energy goesto mainly to ions (O. Klimo et al., Phys. Rev. ST-AB 11 (2008), 031301)

3. Solid targets

Electron energy distributions (1D3V PIC) - interaction of relativistic (I = 1.5×1020 W / cm2)laser pulse with ultrathin (32 nm) overdense (ne = 2.1×1023 cm-3) carbon foil

circular

linear



Ion acceleration by circularly polarized laser

3. Solid targets

(Left) Ion density (1D PIC)and ion velocity distribution

at 28τ

(2D PIC) for flat-top

laser beam (I =

1.5×10

20

W / cm2) incident on 32 nmcarbon foil (O. Klimo et al.,

op. cit) (Right) Experimentalion spectra, 45 fs Gaussian

circularly polarized beam

quasi-monoenergetic ion bunch inlaser interactions with ultra-thin foils,

all ion sorts accelerated to the samevelocity, suited for ions heavier thanprotons, ion energy proportional tofluence (I τ ) independent of λ , needed

high contrast flat-top relativistic laser

5×1020 W / cm2 on 5.3 nm DLC (diamond-like carbon) foil( A. Henig et al., Phys. Rev. Lett. 103 (2009), 245003)



Relativistic double sided plasma mirror via foilRPA (radiative pressure acceleration)

frequency upshift and compression of laser pulse

3. Solid targets

(Up) Conceptual scheme of double-sided plasma mirror (Right) Electric fieldof reflected driver pulse and reflected

source pulse (T.Z. Esirkepov

et al.,

European Phys. J. D 55 (2009), 457 )



Hole boring and ion accelerationcircularly polarized relativistic laser pulse penetrates throughthe corona and simultaneously produces directed ion beam(results may be applied later e.g. at Hiper for ion fast ignition)

3. Solid targets

(Up left) Schematic structure of the piston and theelectrostatic shock maintained by the radiation

pressure (Up middle) Ion density at 190 λ /c. Ion

angular (Up right) and energy (Right) distributionsat 250 λ /c. Laser intensity 4×1022 W/cm2.(N. Naumova et al., Phys. Rev. Lett. 102 (2009), 025002 )



4. Clusters, mass-limited targets

Atomic clusters - efficient absorbers of laser radiation – Coulomb explosion of clusters → energetic ions, hard X-rays

– possible applications - table-top nuclear fusion, nuclear reactions, …

Clusters used to create high energy density plasmasthat drive strong shocks (Mach >50) and radiative blast wave

Simultaneous subpicosecond time framed interferogram (a) and Schlieren image (b)of a radiative blast wave 24 ns after being launched into a medium of 6 nm Ar clustersby a 700 mJ, 750 fs laser pulse. (P.A. Norreys et al., Phys. Plasmas 16 (2009), 041002 )



4. Clusters, mass-limited targets

Mass limited targets – limit transverse spread of energy – Various types of MLT – microdroplets, foil sections

Significant rise in laser energy transformation into fast

protons with decreasing foil section surface

0

5

10

15

0.01 0.1 1 10

Surface (mm²)

(a) (b)

0.01

0.1

1

10

0.01 0.1 1 10

Surface (mm²)

constant thickness

laser Magneticspectrometer

RCF with holevariablesurface

E m a x

( M e V )

C o n v e r s i o

n ( % ) to proton energy convers-

ion efficiency (for protonswith energy >1.5 MeV)

for the same targets, laserI λ2 ~1019 W/cm2×µm2,

350 fs, 45°, focal ∅

6 μm

(Top) Set-up of experiment(a) max. proton energy for

2 µm-thick Au targets ofvarious surfaces (b) laser

(S. Buffechoux

et al. (J.

Psikal), submitted to

Phys. Rev Lett., 2009)



5. Warm dense matter

State of matter – dense matter heated to electron kineticenergy comparable to potential energy – cores of large planets, ICF, …

Warm dense matter – produced at ELI either by laser or by

secondary sources (e.g. proton beam)

(Left) XUV image of proton heating of 60 μm-thick Al foil at D/r=1.5, converted to tem-perature. (Right) X-ray pinhole camera image of a laser irradiated Al hemisphere of

thickness 15 μm and r=180 μm (R.A. Snavely et al., Phys. Plasmas 14 (2007), 092703)



6. Advanced fusion schemes

Physical issues of advancedfusion schemes addressed

– ELI is not designed for

complex ICF experiments – many aspects of fast ignition

and of shock ignition can betested

3D-hybrid-PIC simulation showing acontinuous 1 GA beam of 1 MeV electronswith 120 keV transverse temperature injec-

ted into plasma with density rising expo-nentially from 2 to 100 g/cm3 after 1.2 ps(J. Meyer-ter-Vehn

et al.,

Plasma Phys. Control.

Fusion 47 (2005), B807 )



Applications, technology transfer

Plasma and high energy density physics at ELI will beoriented mainly to fundamental research

Large application potential still exists – optimization of ELI secondary sources will be based on the

fundamental physics of laser target interaction

– material science - ultrafast processes induced in material by laser-

accelerated ion beam, ultrafast response of materials on neutrons and γ-rays probed by synchronized laser and X-ray pulses - vital for under-standing the aging of construction materials of nuclear power plants

– intense and short positron pulses can be used in material analysis

– nuclear transmutation of long-lived radioactive isotopes into lessradioactive or short-lived products will be studied for application innuclear waste management

– ultraintense electric or magnetic lenses for accelerator technology



Conclusions

ELI Beamline facility opens new extremely richhorizons for plasma and high energy density physics

ELI Beamlines facility will be user facility withexperimental program dependent on user proposals,and it is impossible to foresee all research topics

List of prospective research topics is intended forbasic specifications of ELI interaction areas



Thank you for attention

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J.limpouch-Plasma and High Energy Density Physics