Relativistic Laser Plasma Research performed with PW Lasers

2014.4.21. APLS

Chang Hee Nam1,2

1Center for Relativistic Laser Science (CoReLS), Institute for Basic Science (IBS), Korea; 2Dept of Physics and Photon Science,

Gwangju Institute of Science &Technology, Gwangju, Korea

Target

Relativistic Laser Science Laser-Matter Interactions and Related Phenomena

Explored at Relativistic Laser Intensities

Laser Pulse (>1018 W/cm2)

Plasma formation

Ultrahigh current density (> 108 A/cm2)

Relativistic electrons High-energy Protons

Neutrons

Positrons

Nuclear reaction

X-rays γ-rays THz

Electro-static field

Coherent X-rays

Ultrahigh magnetic field (> 1010 Gauss)

Research Plan Exploration of Relativistic Laser-Matter Interactions using

Super-intense Laser Pulses

Extreme Laser Field

Atto/Zeptosecond Science

Relativistic Laser-Matter Interaction

Applications: X-ray, electron, proton

Relativistic Laser-Plasma

Theory

Control of Relativistic Interaction Processes

Overview

1. Femtosecond PW laser system 2. Relativistic Laser Science A. Laser electron acceleration B. High energy proton generation C. Relativistic harmonic generation

• PW Ti:Sapphire Laser (1) Beam line I: 30 fs, 1.0 PW @ 0.1 Hz (2) Beam line II: 30 fs, 1.5 PW @ 0.1 Hz • 100-TW Laser: ∆t = 30 fs, E = 3 J @ 10 Hz

IBS Center for Relativistic Laser Science

Femtosecond oscillator

Pulse stretcher

Pulse compressor

Preamplifier Power amplifier

Ultrashort high power laser output

고출력 펨토초 레이저 기술

Chirped-Pulse Amplification (CPA) Technique

PW Ti:Sapphire Laser

PW Laser Beamlines I & II

Before 2009 2010 2012

1 PW @ 30fs

1.5 PW @ 30fs

Upgrade: High Contrast, 20 fs, 4 PW Laser

1. Femtosecond PW laser system 2. Relativistic Laser Science A. Laser electron acceleration B. High energy proton generation C. Relativistic harmonic generation

Atomic field strength: 92 5.1 10 V/cm;B

B

eEr

= ≈ ×2

16 23.5 10 W/cm8

BB

cEIπ

= ≈ ×

Relativistic Laser Intensities

Intensity for relativistic electron: (Relativistic regime) ( )

182 2

Re 02

1.4 10 W/cmm

I aµ

λ×

≈

Intensity for relativistic proton: (Ultra-relativistic regime) ( )

242

2

4.5 10 W/cmRp

m

Iµ

λ×

≈

0 00 2

0

speed of nonrelativistically oscillating electronspeed of light

NR

e e

eE eA vam c m c cω

= = = =

0When 1, 0.75 .a v c= = 0For 1, relativistic.a >

0For 1800, ultra-relativistic.p

e

Ma

m= =

PW Laser Experimental Area

PW Chamber II

PW Chamber I

Plasma mirror

Compressor II

Compressor I

Laser Wakefield Electron Acceleration

Electrons pushed by ponderomotive force (radiation pressure) of an intense laser pulse Restoring force to the original position Electron plasma wave created Injected electron bunch accelerated by

the plasma wave

Plasma wave by laser pulse ~ Waves by ship in sea

Acceleration by plasma wave ~ Surfing the wave in sea

Huge acceleration field > 100 GV/m

Electron current Gas Jet

Beam profiler

Wavefront sensor

ICT

Lanex Lanex

Dipole magnet

ICCD CCD

Focusing Mirror (f=4m)

Holed mirror

PW laser pusle (E=25~30 J, t=30 fs)

0.5 GeV 1 GeV 2 GeV 3 GeV

Electron energy Electron profile

0 5 -5 X (mrad)

0

5

-5

Y (

mra

d)

0.5 1.0 1.50

50

100

ICT

signa

l (m

V)

Time (µsec)

Double-stage Gas jet

4 mm

10 mm

Experimental Setup for Laser Electron Acceleration

Laser spot wavefront control

FWHM~25 μm

High-energy electron beam (>400 MeV) injected to the second gas jet

Investigation on multi-jet configuration with high energy electron injection

Charge of electron beam (4+10 mm): ~ 80 pC (> 0.5 GeV), ~10 pC (> 2 GeV)

Double-stage Gas jet

de = 2.1x1018 cm-3 (4 mm) ;de = 0.7x1018 cm-3 (10 mm) Electron energy spectrum

0

200

100

dN/d

E (p

C/G

eV)

Energy (GeV) 0.4 0.5 1.0 2 3 5

Multi-GeV e-Beam Generation with Dual Gas Jets

HT Kim et al., PRL (2013)

5.0

3.0

2.0

1.5

1.0

0.7

Electron energy spectrum (GeV)

LANEX 2

LANEX 3

Electron beam profile

LANEX 1

CCD

Al foil LANEX 1

LANEX 2 LANEX 3 Dipole magnet

ICCD ICCD

Gas cell

Concave mirror (f=6m)

PW laser pulse (E=26 J, τ0 =28 fs)

CCD

Electron acceleration using a single gas cell

Electrons over 2 GeV from a 10-mm gas cell Gas cell length = 10 mm Positively chirped 61 fs Intensity = 2x1019 W/cm2 (a0=3.1)

Top view (Thomson scattering)

Electron energy > 2 GeV

0

500

1000

1500

2000

dN/d

E (a

rb. u

nits

)

4.0 3.0 2.0 1.5 1.0 0.7

Electron energy (GeV)

Electron energy spectrum

Smooth propagation over the whole medium length of 10 mm

Laser Proton/Ion Acceleration Acceleration mechanism laser Target

thickness Characteristics Energy

scaling TNSA

(Target normal sheath acceleration)

I>1018 W/cm2

Linear pol. ~μm Broad spectrum, Thermal electrons

RPA (Radiation pressure

acceleration)

I>1020 W/cm2

Linear pol. Circular pol.

~nm

Quasi-monoenergetic,

collective electrons

Laser, not penetrating the target, heats electrons, which drag protons after penetrating the target.

μm-thick

Laser pulse pushes electrons as a whole, which drag protons.

nm-thick

2

Radiation Pressure Acceleration: Light Sail

electrons

Coulomb force

Protons/ions

laser pulse

PW Target chamber for proton experiment

OAP f = 80cm; 60cm

Target surface monitor

Target

Focal spot monitor

CR39

To Thomson Parabola

Target: polymer, DLC, Al Thickness: μm to 10 nm Intensity range w/ PM: 5x1019 W/cm2 – 7x1020 W/cm2 Pol.: s-pol or circular pol. on target Incident angle: 7 - 9 deg. to normal

PW Plasma mirror: contrast enhancement

Plasma formation on double plasma mirrors

Temporal profiles measured with a third-order cross correlator. Contrast 10-8 (w/o PM) -> 10-12 (w/ PM) Contrast enhancement: 104

Target and Thomson parabola

Proton and C6+ measured with Thomson parabola

Target: 10-nm-thick polymer Laser intensity: 3.3 × 1020 W/cm2.

Proton energy: 45 MeV

IJ. Kim et al., PRL 111 (2013)

RPA with CP laser pulses: Experiment No oscillating term in radiation pressureNo heating J B×

Circular pol., 30fs, 6.1x1020 W/cm2, 15 nm polymer

Proton and C6+ spectra measured with Thomson parabola

Generation of 80 MeV protons!

Scaling of maximum proton energy to laser intensity

2 3 4 5 6 70

102030405060708090

Laser Intensity (x1020W/cm2)Max

imum

pro

ton

ener

gy (M

eV)

CP, 15 nm LP, 20 nm

CP: Quadratic scaling LP: Linear scaling

Outperformance of the CP case over the LP

Clear difference between LP and CP cases confirms the favorable role of CP laser pulses in RPA

Relativistic Electrons

High Energy Protons

X-rays, γ-rays

Coherent Atto/Zepto X-rays

Research Overview Journey into the deeper space-tim

e

Proteomics

Atto/Zepto science

Laser nuclear physics

Lab astrophysics

Synthesized Super-intense

Laser Pulse

Target

Fundamental LMI

Harnessing laser science at relativistic conditions “Matter under extreme environments”

“New horizon in time & space” “Discovery of novel physical processes”

Exploration of Relativistic Laser-Matter Interactions using Super-intense Laser Pulses

Contributors and Collaborators CoReLS/IBS; APRI/GIST Tae Moon Jeong, Jae Hee Sung, Seong Ku Lee, Hwang Woon Lee

S. Ter Avetisyan, I Jong Kim, Il Woo Choi, Himanshu Singhal K. Nakajima, Hyung Taek Kim Ki Hong Pae, Chul Min Kim Kyung Taec Kim, Hyuk Yun, Kyoung Hwan Lee, Dong Hyuk Ko Chang-Lyoul Lee

LOA (Laboratoire d’Optique Appliquée) V. Malka, F. Sylla, B. Vauzour, A. Flacco ELI-Beamlines; HiLASE; Czech Tech. Univ. T. Mocek, D. Margarone, O. Klimo, J. Limpouch, G. Korn

ILE/Osaka Univ. M. Murakami, N. Sarukura, K. Yamanoi, T. Shimizu

KAERI Y. Rhee