APLS 2014.4.21. Relativistic Laser Plasma Research performed with PW Lasers Chang Hee Nam 1,2 1 Center for Relativistic Laser Science (CoReLS), Institute for Basic Science (IBS), Korea; 2 Dept of Physics and Photon Science, Gwangju Institute of Science &Technology, Gwangju, Korea
Relativistic Laser Science Laser-Matter Interactions and Related Phenomena Explored at Relativistic Laser Intensities Coherent X-rays Target Positrons Laser Pulse (>10 18 W/cm 2 ) High-energy Protons Relativistic electrons Plasma formation Ultrahigh current density (> 10 8 A/cm 2 ) Ultrahigh magnetic field (> 10 10 Gauss) Nuclear reaction Electro-static field Neutrons X-rays γ-rays THz
Research Plan Exploration of Relativistic Laser-Matter Interactions using Super-intense Laser Pulses Atto/Zeptosecond Science Relativistic Laser-Plasma Theory Relativistic Laser-Matter Interaction Extreme Laser Field Control of Relativistic Interaction Processes Applications: X-ray, electron, proton
Overview 1. Femtosecond PW laser system 2. Relativistic Laser Science A. Laser electron acceleration B. High energy proton generation C. Relativistic harmonic generation
IBS Center for Relativistic Laser Science 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
Femtosecond oscillator 고출력펨토초레이저기술 Chirped-Pulse Amplification (CPA) Technique Power amplifier Preamplifier Pulse stretcher Pulse compressor Ultrashort high power laser output
PW Ti:Sapphire Laser
PW Laser Beamlines I & II Before 2010 2012009 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
Relativistic Laser Intensities Atomic field strength: E B e = r 9 5.1 10 V/cm; 2 B I B 2 ceb = 3.5 10 W/cm 8π 16 2 a ee ea speed of nonrelativistically oscillating electron v = = = = m c mc speed of light c 0 0 0 2 eω0 e NR When a = 1, v = 0.75 c. For a 0 > 1, relativistic. 0 Intensity for relativistic electron: 1.4 10 2 (Relativistic regime) ( λ ) I 18 2 2 Re a0 W/cm µ m For a 0 M p = = 1800, ultra-relativistic. m e Intensity for relativistic proton: Rp 2 (Ultra-relativistic regime) ( λ ) I 4.5 10 µ m 24 W/cm 2
PW Laser Experimental Area Compressor II PW Chamber II PW Chamber I Plasma mirror Compressor I
Laser Wakefield Electron Acceleration Plasma wave by laser pulse ~ Waves by ship in sea Acceleration by plasma wave ~ Surfing the wave in sea 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 Huge acceleration field > 100 GV/m
Experimental Setup for Laser Electron Acceleration PW laser pusle (E=25~30 J, t=30 fs) Focusing Mirror (f=4m) Electron current ICT signal (mv) 100 50 0 0.5 1.0 1.5 Time (µsec) Dipole magnet Lanex Lanex Gas Jet ICT Beam profiler Holed mirror Wavefront sensor Double-stage Gas jet 10 mm 4 mm ICCD CCD Electron energy 0.5 GeV 1 GeV 2 GeV 3 GeV Electron profile Y (mrad) -5 0 5-5 0 5 X (mrad) Laser spot wavefront control FWHM~25 μm
Multi-GeV e-beam Generation with Dual Gas Jets Double-stage Gas jet d e = 2.1x10 18 cm -3 (4 mm) ;d e = 0.7x10 18 cm -3 (10 mm) Electron energy spectrum 200 High-energy electron beam (>400 MeV) injected to the second gas jet Investigation on multi-jet configuration with high energy electron injection dn/de (pc/gev) 100 0 0.4 0.5 1.0 2 3 5 Energy (GeV) Charge of electron beam (4+10 mm): ~ 80 pc (> 0.5 GeV), ~10 pc (> 2 GeV) HT Kim et al., PRL (2013)
Electron acceleration using a single gas cell CCD Concave mirror (f=6m) Al foil LANEX 1 Dipole magnet LANEX 2 LANEX 3 Gas cell PW laser pulse (E=26 J, τ 0 =28 fs) CCD ICCD ICCD LANEX 1 LANEX 2 LANEX 3 Electron beam profile 5.0 3.0 2.0 1.5 1.0 0.7 Electron energy spectrum (GeV)
Electrons over 2 GeV from a 10-mm gas cell Gas cell length = 10 mm Positively chirped 61 fs Intensity = 2x10 19 W/cm 2 (a 0 =3.1) Electron energy spectrum 2000 Top view (Thomson scattering) dn/de (arb. units) 1500 1000 500 0 4.0 3.0 2.0 1.5 1.0 0.7 Electron energy (GeV) Smooth propagation over the whole medium length of 10 mm Electron energy > 2 GeV
Laser Proton/Ion Acceleration Acceleration mechanism laser Target thickness TNSA (Target normal sheath acceleration) RPA (Radiation pressure acceleration) I>10 18 W/cm 2 Linear pol. I>10 20 W/cm 2 Linear pol. Circular pol. ~μm ~nm Characteristics Broad spectrum, Thermal electrons Quasimonoenergetic, collective electrons Energy scaling 2 μm-thick Laser, not penetrating the target, heats electrons, which drag protons after penetrating the target. nm-thick Laser pulse pushes electrons as a whole, which drag protons.
Radiation Pressure Acceleration: Light Sail laser pulse electrons Protons/ ions Coulomb force
PW Target chamber for proton experiment Target: polymer, DLC, Al Thickness: μm to 10 nm Intensity range w/ PM: 5x10 19 W/cm 2 7x10 20 W/cm 2 Pol.: s-pol or circular pol. on target Incident angle: 7-9 deg. to normal OAP f = 80cm; 60cm Target surface monitor CR39 Target Focal spot monitor To Thomson Parabola
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: 10 4
Target and Thomson parabola
Proton and C 6+ measured with Thomson parabola Target: 10-nm-thick polymer Laser intensity: 3.3 10 20 W/cm 2. Proton energy: 45 MeV IJ. Kim et al., PRL 111 (2013)
RPA with CP laser pulses: Experiment No oscillating term in radiation pressure No J B heating Circular pol., 30fs, 6.1x10 20 W/cm 2, 15 nm polymer Generation of 80 MeV protons! Proton and C 6+ spectra measured with Thomson parabola
Scaling of maximum proton energy to laser intensity Maximum proton energy (MeV) 90 80 70 60 50 40 30 20 10 0 CP, 15 nm LP, 20 nm 2 3 4 5 6 7 Laser Intensity (x10 20 W/cm 2 ) 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
Research Overview Lab astrophysics Synthesized Super-intense Laser Pulse Target Fundamental LMI High Energy Protons Relativistic Electrons Coherent Atto/Zepto X-rays X-rays, γ-rays Proteomics Atto/Zepto science Laser nuclear physics Journey into the deeper space-time
Exploration of Relativistic Laser-Matter Interactions using Super-intense Laser Pulses Harnessing laser science at relativistic conditions Matter under extreme environments New horizon in time & space Discovery of novel physical processes
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