Annapolis, MD, USA • June 13-18, 2010

Overview of Laser-Plasma Acceleration Programs in Asia

Z M Sh J ZhZ.M. Sheng, J. ZhangDepartment of Physics, Shanghai Jiao Tong University, China

and Institute of Physics, CAS, Beijing, China

Acknowledgements

Kazuhisa NakajimaHigh Energy Accelerator Research Organization (KEK), JapanTomonao HosokaiPhoton Pioneers Center, Osaka University, JapanS. V. BulanovKansai Photon Science Institute, JAEA, JapanShigeo KawatagGraduate School of Eng./CORE, Utsunomiya Univ., Japan

P. D. GuptaRaja Ramanna Centre for Advanced Technology, Indore, Indiaj gy, ,G. Ravindra KumarUPHILL, Tata Institute of Fundamental Research, Mumbai, India

Baifei Shen, Ruxin Li, Zhizhan Xu, ,Shanghai Institute of Optics and Fine Mechanics, CAS, ChinaYutong Li, Liming Chen, Zhiyi WeiInstitute of Physics, CAS, Beijing, ChinaYuqiu Gu, Hansheng Pengq , g gLaser Fusion Research Center, CAEP, Mianyang, ChinaChuanxiang Tang, Wenhui HuangTsinghua University, Beijing, China

Outline

Overview of the Asian ActivitiesOverview of the Asian Activities

Progress on electron acceleration in China

Progress on ion acceleration in China

Concluding remarksg

GIST-APRI, KoreaCAS-IOP, ChinaCAEP-LFRC, China

300TW720TW 300TW

CAS-SIOM, ChinaPotential for laser acceleration

in Asia: ~ 10 labs having >10TW lasers

890TW

in Asia:   10 labs having  10TW lasers

890TW

100TW

JAEA KPSI Japan

100TW

JAEA-KPSI, Japan

RRCAT, India150TW

NCU, Taiwan100TW

The 2nd Asian Summer School on Laser Plasma Acceleration and Radiations

August 6-10, 2007, Kyoto, Japan

The 4th Asian Summer School on Laser Plasma Acceleration and Radiations

August 17-21, 2009, Hsinchu, Taiwan

Development of laser facilities at IoP, CAS

1999 2001 20062002

XL-I laser system XL-III laser systemXL-II laser system

1.4 TW(1999)

350 TW(2006)

20 TW(2002)

Xtreme Light III laser system upgraded to 720TW

Institute of Physics CASPhysics, CAS, Beijing

XL-III laser720TW/30fs/22J

Target area andTarget area and diagnostics

The group at IoP, CAS in Beijing g p , j g

• Fast ignition related physics (fast electrons, ions);• Propagation of fs laser pulses in air and plasmas;Propagation of fs laser pulses in air and plasmas;• Laser plasma acceleration for electrons and ions;• Novel laser-based radiation sources (THz, x-ray,Novel laser based radiation sources (THz, x ray,

X-ray lasers) and applications;• Ultrafast electron diffraction;Ultrafast electron diffraction;• Laboratory astrophysics;• Theory and simulations on above subjectsTheory and simulations on above subjects

High contrast Ar K-shell keV source

104

ad2 ) Cu bulk

Ar gasAr K

Cu Kα

Experimental setupX-ray spectrum

Probe beam CCD

Phosphor

103

ph/k

eV/m

ra Cu Kα

LaserBe foilKnife edge

Phosphor screen

e-

Nozzle

102Inte

nsity

(pX-ray CCDShadowgraph

CCD

Magnet

Source imaging on CCD

5 10 15

Photon Energy (keV)No energetic tail

High contrast: peak/bkgd>20Pure, clear

High contrast: peak/bkgd>20EK/Etotal>70%

Quasi-monochromaticIntense: B=1020 phs/s/mm2/mrad2

25000

30000 Rayleigh scattering measurement

Coherent (small size=12 µm)Directional: ILong./ITrans.>10

Continuum background 5000

10000

15000

20000

Inte

nsity

(a.u

.)

Cluster formed Continuum background ΣNKα/ΣNxray ~ 10%--polychromatic

1 2 3 4 5 6 70

5000

Backing pressure (MPa)

New progress: Ar keV flux x10 !!

EL(mJ) 800

(f ) 28

1.5x104

D

LaserNozzlex

y 0.2 mm

τ (fs) 28

Contrast(ps ASE)

>109

(adj.)

1.0x104

s on

CC

D

(p ) ( j )Ipeak (W/cm2) 8x1018

Kα flux 1.1x104

5.0x103

Pho

tons Single-shot-imaging available !!

(phs/mrad2)Size (µm) 20

Brightness 3 6x1021

0 2 4 6 8 10 12 14 160.0

Target displacement (mm)

With bkgd High contrastPhoton flux on IP:5x106 phs/cm2

Brightness(phs/s/mm2/mrad2)

3.6x10Target displacement (mm)

L.M.Chen et al., PRL,104, 215004(2010)

New facilities to produce 4 beam lines for potential applications at SJTU

Laser-driven i l

keV X-ray particle beams

coherent source

40TW + PW laser systems

MeV ultrafast MW highPotential applications: condensed matter physicsMeV ultrafast

electron imaging

MW high power THz

source

condensed matter physics, medical applications, laser fusion, etc.g g ,

LPA medical system R&D with Robotics

Robotic Particle Beam Therapy System

Robotic Particle Beam Therapy System Laser-driven x-ray Imaging

Laser-driven IGPT (Image Guided Proton Therapy)Guided Proton Therapy)

1 PW 10HzLaser System

Laser-drivenProton Source

Online PET

Using 500fs electron beams to diagnose the plasma dynamics

AdjustableThin film Adjustable delay

Thin film sample

t

BS

t1t2

Frequency tripler

80m

BS

p 0n

60keV-500fs Ultrafast electron diffraction imaging system

890TW/30fs CPA Short Pulse LaserState Key Laboratory of High Field Laser Physics, SIOM, CASState ey abo ato y of g e d ase ys cs, S O , C S

Electron acceleration with gas and capillary is now being done Proton acceleration with foil is planedbeing done. Proton acceleration with foil is planed.

This system is based on CPA scheme, with a peak power of 890TW and a pulse duration of 29fs. It consists of a Ti:sapphire oscillator, a pulse stretcher, four stages of amplifiers and a four-grating pulse compressor.

Laser acceleration experiment at LFRC CAEPLFRC, CAEP

4cm ablative capillary

300TW 30fs laserSILEX, CAEP, China

Accelerator Lab of Tsinghua University• FacultyFaculty

– 15 faculties and more employee– About 20 graduate studentsAbout 20 graduate students

• Research Activities– Low Energy Linear Accelerators and Their Low Energy L near ccelerators and he r

Applications– Fundamental Accelerator Physic and y

technology• High brightness electron injectors • Electron beam and laser beam interaction • Electron beam and laser beam interaction • Accelerating Structures• Beam dynamics

Research on Thomson scattering X-ray

Control Room

RF Power S

Cooling Water

Source

UV & TW

UV Laser

TW Lasers TW fs

LaserLaser

x-ray

Thomson scattering experiment with photocathode exper ment w th photocathode

RF gun and TW laser

800nm, 3TW,30fs

266nm, 1mJ, 30fs

50MW,50Hz

S b t i t ll ti l t dSubsystem installation completed

Experiment of head-on injection at JAEA-KPSI

Japan

JAEA-KPSI

Driver pulseE=400 mJ τ=40 fs

Injecting pulseE=30 mJ τ=50 fs

100TW J-KAREN

E=400 mJ, τ=40 fsφ=34 µm, I=3x1018 W/cm2

E=30 mJ, τ=50 fsφ=50µm, I=8x1016 W/cm2

He: 0.7 MPa ; ne~1x1019 cm-3Mono-energetic electron beamMono-energetic electron beam

Q=8.7 pC

p=134 MeV/c (FWHM 11MeV/c)

Momentum (MeV/c)

p 134 MeV/c (FWHM 11MeV/c)

θFWHM=4 mrad

H. Kotaki, et al., Phys. Rev. Lett. 103, 194803 (2009). 

Stable e-beam generation by multi-stage ionization scheme

30Helium target

30Helium targetHe◆ H

>1 MeV electrons Laser: E=160 mJt=40 fs

100 d10

20

Helium targetArgon target

al (m

rad)

10

20

Helium targetArgon target

al (m

rad)

◆ He ● Ar

Pointing stability(RMS)

t=40 fsI=9x1017 W/cm2

100 mrad

-10

0tin

g in

ver

tica

-10

0tin

g in

ver

tica

Ar θ=2 4mrad@Arθ=9.8mrad@He

for 50 shots

-20

-10

Poin

t

-20

-10

Poin

tAr θ=2.4mrad@Ar

Beam divergencefor 50 shot(RMS)

100 mrad-30

-30 -20 -10 0 10 20 30

Pointing in horizontal (mrad)

-30-30 -20 -10 0 10 20 30

Pointing in horizontal (mrad)Speed x100θ=29.8±8.8mrad@He

θ=10.4±2.0mrad@Ar

for 50 shot(RMS)

Argon (neutral gas density: 0.5x1019 cm-3)Helium (neutral gas density: 2.2x1019 cm-3)

Pointing stability in Ar is 4 times better than that in HeM Mori et al., Phys. Rev. ST-AB 12, 082801 (2009)

Energy Increase in Ion Acceleration via Cluster Target

Soft X ray spectrum Long channel

Tenfold improvementin maximum ion energy

of sub-critical plasma created in cluster target

Ion detectionusing CR39 stack

・Ions, accelerated up to 10-20 MeV/u (Carbon) are detected.Diff t i f th ti l TNSA i

Y. Fukuda et al., Phys. Rev. Lett. 103, 165002 (2009)

→ Different regime from the conventional TNSA scenario.・2D-PIC simulation predicts that Magnetic-Field-Assisted-TNSA might work.

Unlimited Ion Acceleration by Radiation Pressure

In the radiation pressure dominated regime, ion energy can be greatly enhanced by a transverse expansion of a thin target. The expansion decreases the number of accelerated ions in the irradiated region increasing the energy of the remaining ions In the relativistic limit the ions become phase locked with respect to thethe energy of the remaining ions. In the relativistic limit, the ions become phase-locked with respect to the electromagnetic wave resulting in an unlimited ion energy gain. This effect and the use of optimal laser pulse shape provide a new approach for great enhancing the energy of laser accelerated ions.

Evolution of thin shell irradiated by a

strong electromagnetic wave

Equations of motion

0 0t i ijk j kp x x

n l η ηε∂ = ∂ ∂P

Laser-Mass-Limited-Target interaction in Radiation Pressure Dominated Acceleration

regime: PIC computer simulation

2 2

2

, , 1,2,3

it i

k k

L

cpxm c p p

i j kE c

α

∂ =+

=

+P v2

L

cπ=

−P

v1/52 0 0

3/53

0 0

125( )

48L y z

x

Ep t m c t

n l m cαα

π ππ

⎛ ⎞= ⎜ ⎟

⎝ ⎠Laser pulse, reflected

radiation and Mass Limited Target

Electron and ion energy and density v.s. time

Inset: ion energy spectrum

( )k

x

k

p t tm cα τ

⎛ ⎞= ⎜ ⎟

⎝ ⎠( )0 0

0

1 ( ') 'txt t dt

cψ ω ω β⎛ ⎞= − = −⎜ ⎟

⎝ ⎠ ∫

Asymptotic solution for ion momentumdependence on time

Wave phase: For

gy p

⎝ ⎠1 2

00 1/ 2

( / ) 2 1 2 11 2 2 2

kk k

kt k k

k k kt

τ ω τω τπ

− − +⎛ ⎞ ⎛ ⎞→ + Γ Γ⎜ ⎟ ⎜ ⎟− ⎝ ⎠ ⎝ ⎠→ ∞

If k<1/2, the phaseIs locked

S. V. Bulanov et al., Phys. Rev. Lett. 104, 135003 (2010)S. V. Bulanov et al., Phys. Plasmas 17, in press (2010)

Repeatable e-beam generation by LWFA with a plasma micro optics

Photon Pioneers Center, By T.HosokaiOsaka University

(1) (2) (3)9 successive shotsAxal external B-field

~ up to 1T

By T.Hosokai

50mm

(4) (5) (6)

up to 1T

(7) (8) (9)

B=0.2TShadow graph image

( ) ( ) ( )

Experimental setupTransverse geometrical emittance

~0.02π mm mrad

EB=0.2T B=0

Experimental setup

#He Gas ~4x1019cm-3

E

F#=3.5 ( f = 178mm)

Laser 6 ~ 12 TW( / 2)

60 mme-beam profile

T.Hosokai,et al.,Phys Rev.Lett. 97, 075004 (2006 )

Focal spot ~ 5-7µm(1/e2)Rayleigh length ~50µm

Photon Pioneers Center,Osaka University

Demonstration of 2-staged LWFAOsaka University

*Shadowgraph:1.2ps before main pulse

Typical e-beam profile

B i thBy increase the picosecond pedestal pulse energy and B fieldsfields

7.0

6.0

5 0

(x103)

b. u

nits

] (a) (b) (c)~100MeV

2 mm channel700µm channelThermalNo channel5.0

4.0

3.0

on s

igna

l [ar

b

~50MeV ~100MeVNo channel~20pC

T Hosokai et al2.0

1.0

Electron Energy [MeV]0 25 50 75 100 0 50 100 150 200

Electron Energy [MeV]0 50 100 150 200

Electron Energy [MeV]

Ele

ctro T.Hosokai,et al.,

Appl. Phys. Lett. 96,121501 (2010)

Summary: Dream of Laser AcceleratorsS. Kawata/Utsnomiya Univ.

/ Atto physics – Atto Second~ 10-18sec

＝＞ Compact Accelerator Pre-accelerated elecronbeam is compressed and confined to produce an atto-second high-density p y

－> One can observe ---・electron motion in an atom・light wave behavior x x

atto-second high-density e-bunch by a short-pulse TEM10+01 mode laser.

・electron motion in chemical reaction~150atto second <- electron movement time scale in Hydrogen atom

xy

x

[λ]

T=0[λ/c]Resultsbunch size: Transverse（Y）: 4.81λ

Longit dinal（Z） 0 187λ ( 500 attosecond) x[Longitudinal（Z）: 0.187λ (～500 attosecond) Averaged energy ~231 (MeV)Normalized transverse rms emittance 0.96 (π mm mrad)Momentum spread 3 5%

x[λ]

T=5000[λ/c]Momentum spread 3.5%Number density 43 times n0

25

xz[λ]

Summary: Dream of Laser AcceleratorsS. Kawata/Utsnomiya Univ.

/ High-quality laser ion beam・Cancer therapy・Ion Inertial fusionIon Inertial fusion

Results: 1. Collimation!2. High-efficiency!: laser -> ions > ~26%; 2. High efficiency!: laser > ions > 26%;

laser->Proton energy conversion>13~15%

λ 500fs

X/λX/λ

Y/λ

X/λX/λCollimation!

High-efficiency!Structured target enhances laser-to-ion energy conversion efficiency. Backside

structure produces a collimated ion beam. Al + CH-ion source structured target: periodic array with structure composed of boxes of 60 nm × µm separated by 0.25 µm, material composition C6+, density 0.35 g/cm3

p

26

＝＞ Flat target: 2.8% (Laser -> ions)Structured target: 26%(Laser -> ions) case 3(20% C, 6%Protons)

Stable electron beams from 1 cm Gas jet and Gas-fill capillary accelerator at GIST

Mean electron energy = 236.9 MeVSD/Mean E = 5 %

and Gas fill capillary accelerator at GISTGIST-APRI 100TW laser

Capillary Accelerator

Korea

Intensity (arb.u.) Intensity (arb.u.)

Charge: ~100pCDivergence angle: ~a few mrad

300TWCapillary Accelerator experiment under collaboration with GIST(Korea),

(mra

d)

with GIST(Korea), Oxford Univ. (UK), KEK/JAEA(Japan)

nce

Ang

le (

Div

erge

n

Electron Beam Energy (MeV)

(N. Hafz et al., nature photonics, 2, 571, 2008)3 cm Gas-fill Capillary

LaserLaser--plasma based acceleration of electrons plasma based acceleration of electrons at RRCAT Indore Indiaat RRCAT Indore India

Laser Parameters10 TW Ti:sapphire Laser

at RRCAT, Indore, Indiaat RRCAT, Indore, India G. P. Gupta

Pulse duration - 45 fsPulse energy - 450 mJ

Focal spot

Peak power - 10 TW

Pre-pulse contrast - 106

Experimental set-up E-beam profileSupersonic helium gas-jet

Without magnetSupersonic nozzle Interferogram of

helium gas-jet

Self-modulated laser wake-field acceleration regime IEEE Trans. Plasma. Sci . 2008

Without magnet

LaserLaser--plasma based acceleration of electrons plasma based acceleration of electrons at RRCAT Indore Indiaat RRCAT Indore India

Mono-energetic electron

at RRCAT, Indore, Indiaat RRCAT, Indore, India G. P. Gupta

Mono-energetic electron beam occurred over a very narrow range of plasma density

New J. Phys. 12, 045011 (2010)

Peak energy : 10 50 MeV

8 5 1019 3 6 5 1019 3

Peak energy : 10 – 50 MeV

Energy spread : 4 – 8 %

Divergence (θ) : 4 7 mradne ~ 8.5x1019 cm-3 ne ~ 6.5x1019 cm-3 Divergence (θ) : 4 – 7 mrad

Charge : 10 – 60 pCIL = 2.4×1018 W/cm2IL = 1.2×1018 W/cm2

The power of HEDS‐T 3 : See Plasma Dynamics  “as it happens”

R. KumarTIFR 20 TW, 30 fs CPA (100 TW by 2010)

800 nm fs

P‐polarized L P

800 nm, fs

To Polarimeter/Target 

Laser Pump

Pump‐Probe Experiments :

/Spectrometer/Interferometer/…

Probe(Time Delayed

400 nm, fsHot electron currents,Giant magnetic fields,

w. r. t. Pump)

30

Plasma motion…….

Measured Magnetic Field of Relativistic ElectronsNew Results !

Time Resolved , Space IntegratedFront

R. Kumar

Target Front k

FrontAluminium film coated glass

Target Front Target Back

60

70

12

14

30

40

50

MG

)

8

10

G)

10

20

30

B (M

2

4

6

B (M

G

0 1 2 3 4 5 6 7 80

10

Ti ( )0 20 40 60 80 100

0

2

31

Time (ps) Time (ps)

5 x 1018 W cm-2 2 x 1018 W cm-2

Outline

Overview of the Asian Activities

Progress on electron acceleration in China

Progress on ion acceleration in Chinag

Concluding remarksConcluding remarks

Experimental setup for electron acceleration with SILEXacceleration with SILEX

F/8 7By Yuqiu Gu et al.

F/8.7

160mm

Gas nozzle and laser focusing

By Yuqiu Gu et al.

Focusing lens F/8.7 OAPg

Φ=15μm (FWHM) （11％）

Φ=30μm (1/e2)（20％）Φ 30μm (1/e )（20％）

Contrast ratio better than 105

Self-guiding and soliton formation in Plasmas with SILEX at LFRC of CAEP

Thomson Scattering10 mm 400 μm

By L.M. Chen et al.

Laser axis

B diSide view(S-plane)

10 mm

Channel length ~ 10 mm( > 10 diffraction distance)

BendingDiffraction cone( p )

No. 0509260273.0 J, 4.0 MPa

( 10 diffraction distance)Laser propagation show bendingThe “atoll” structure shows plasma cavity --- the density valley ascribes to the postsoliton.

No. 0509260193.2 J, 2.5 MPa

y y pL. M. Chen et al, Phys. Plasmas 14, 040703(2007)

P > Pcr; Pulse length llas > Plasma wavelength λw (λw~2πc/ωp)

2.1 J, 3.0 MPa llas > λw

(plasma imaging) 410-532nm

1.9 J, 1.5 MPa llas < λw

Three energy peaks were observed

Laser power:181TW /Gas Pressure: 4.23MPa

Shot No.104 By Yuqiu Gu et al.

p /

80MeV53MeV

C

80MeV53MeV63MeV

800

1000

)

400

600

Inte

nsity

(A.U

)

0

200

0 20 40 60 80 100 120 140 160 180 200

Energy(MeV)

Electron spectrum from 10mm‐long gas column

By Yuqiu Gu et al.

xCCDband-pass filter

zE

300

Laser

y

zblue-pass filter

CCD ICT-integratedyCCD ICT integrated total charge 15nC

Laser plasma acceleration experiment is underway,using PW laser and capillary at SIOM CASusing PW laser and capillary at SIOM, CASunder collaboration with KEK

5 cm capillary Optical guiding

Recently successful optical guiding ofoptical guiding of160TW (8J, 50fs)was achieved

Setup with side-laser triggering ablative capillary acceleration driven by PW laser

Laser plasma acceleration experiment is underway at IOP, CAS  with XL‐III

Setup for LPA experiments with gas jet

(under collaboration with IHEP and KEK)

20 μm spot size

and gas-fill capillary discharge plasma

20 μm spot size72% focusing

Hydrogen gas

Laser

Electron

3 cm3 cm

Discharge device Ceramic gas-fill capillary

Electron injection into a laser wakefield by fi ld i i i hi h h ffield ionization to high‐charge states of gases

Pump pulse

Totalpulsea~ 2

Neon Ionization injectiongas injection

Injection pulse a~5

Self-injectiona 5

M. Chen et al., J. Appl. Phys. 99, 056109 (2006)

Electron Injection with a transversely propagating weak pulse: colinearly polarizedpropagating weak pulse: colinearly‐polarized

Pump pulsepulse

Injection pulse a~0.1

W.M. Wang et al., APL 93, 201502 (2008)

Electron injection triggered by a nanowire

Gas 6 x 10 18 cm‐3

Nanowire (0.7 x 0.7 μm2, 1.2 x 10 21 cm3)

Gas 6 x 10 cm

Laser

30 fs 460 

y

mJ

The wire is at x=200 μm, z=6.35 μm.

xz

Baifei Shen et al., Phys. Plasmas, 053115(2007)

The energetic electron bunch is found to have a highly regular sinusoidal structure in thehighly regular sinusoidal structure in the 

polarization plane of the laser. 

The period of the sinusoidal e pe od o t e s uso dastructure changes from about 660 nm to about 800 nm  

We conclude that the betatron oscillations are driven directly by the laserField.

Laser‐driven coherent betatron oscillation in a laser‐wakefield cavity,  BF Shen with colleagues at ANL, Phys. Rev. Lett. 100, 095002 (2008).

Cross‐Modulated Laser Wakefield Acceleration(XM‐LWFA) partially confirmed in experiment(XM LWFA), partially confirmed in experiment

PlasmaPlasma waveAmplifying a

seeding l

Pulse-1Pulse-2plasma wave

Advantages: 1. Using pulses with relatively low intensities;g p y2. Timing unnecessary for laser injections;3. More controllable than the self-modulated laser wakefield accelerators;4. Allowing for efficient energy transfer from laser to plasma waves

Z M Sh t l Ph Pl 9 3147 (2002)Z.-M. Sheng et al., Phys. Plasmas 9, 3147 (2002).

W.-T. Chen et al., Phys. Rev. Lett. 92, 075003 (2004).

Fast electron emission for incidence angle 70°

+20° Front

200°

+20 Front

200Target surface

-20° Rear

70°

0 ea

Angular distributions of > 300keV fast electrons in the incident

Typical patternCone angle <15° (FWHM)

plane.

A fast electron jet along the front target surface is observed

Cone angle 15 (FWHM)

A fast electron jet along the front target surface is observed.Y.T. Li et al., Phys. Rev. Lett. 96, 165003 (2006).

2D PIC simulations show that a kind of inverse free electron laser acceleration occurs at the target surface

60

SpecularA

electron laser acceleration occurs at the target surface

Fast electrons move along the surface in a oscillating form.

40

50

0) Laser

pdirection

30

40

50

Y/λ

0

(a)

P1P2 (1)

(2)

P3

1.0007.00013.0019.0025.00

20

30

Y (λ

0 Laser

Target region

10 20 30 40 50 60

20

30X/λ

0

P3

(2)

(1)

γ

0 10 20 30 40 50 6010

X (λ )

Target region10 20 30 40 50 60 70

0

10P1

(2)γ

t/T0

(b)

X (λ0)

(a) Bz (b) E⊥

Quasi-static magnetic and electric fields are self-induced around the surface.

A h b fAs soon as the betatron frequency approaches the laser frequency, resonant acceleration occurs.

M. Chen et al., Opt. Express 14, 3093 (2006)

Quasi‐monoenergetic electron bunches in laser interaction with a wire targetlaser interaction with a wire target

Y. Y. Ma et al., Phys. Plasmas (2006).

Outline

O i f th A i A ti itiOverview of the Asian Activities

Progress on electron acceleration in China

Progress on ion acceleration in China

Concluding remarksConcluding remarks

Laser Interaction with Clusters

TW Laser：100-160mJ, 60fs, 10Hz

PW Laser：1－5.4J, 50fs, single shot

Pl h l•Plasma channel•Molecular density and cluster size•Ion energy•Neutron detection

By Haiyang Lu, G NiGuoquan Ni

With CD clusters with bigger size and higher density to achievehigh D+ energy (Emax~90keV ， Eaver~30keV) ， and achieveneutron yield at 2 1 ×106/J 50 times larger than reported byneutron yield at 2.1 ×106/J, 50 times larger than reported byother lab

Haiyang Lu et al. Phys.Plasmas 16,083107(2009)

107

2 1×106/J100

Maximum Kinetic energy CD

y g y , ( )Haiyang Lu et al. Phys.Rev.A 80,051201(R)(2009)

106

n Y

ield

2.1×106/J

60

80gy

(keV

)

CD4

D2Madison et al. ， Phys.

4

105

on N

eutro

n

M di l ， Ph4×104/J

40

60

n En

ergy

(

Ditmire et al., Nature (1999)

CD4

D

Plasmas (2004)

103

104

Fusi

o Madison et al. ， Phys. Plasmas (2004)

0

20Ion

Averge Kinetic energy D2

0.1 1 10Laser Energy (J)

0 1 2 3 4 5 6Laser Energy (J)

Back pressure 80bar，CD4 cluster diameter 12nm，atom density for D 1.5 ×1019cm-3,

50

Back pressure 80bar，CD4 cluster diameter 12nm，atom density for D 1.5 ×10 cm ,Peak intensity Ipeak=1.5×1019W/cm2，Pulse duration 50fs, Laser energy 5.4J，Neutron yield 5.5 ×106

Bulk ion acceleration in foam target

Solid target: Surface acceleration

Foam target: bulk acceleration

Neutron yields for different targets

8000

J6000

8000

160mg/cc 50mg/cc600

800 160mg/ccsolid

eutr

on/J (a) (b)

2000

4000

200

400

ber o

f ne

1.5 2.0 2.5 3.00

1.5 2.0 2.5 3.0 3.50

Num

b

Detecting angle 76o Detecting angle 16o

Neutron yields for foam targets are higher than that for solid. This confirms the bulk acceleration.

Y.T. Li et al., Phys. Rev. E (2005).

Effect of large prepulse on high energy ions:Shock waves produced by the prepulse lead to large divergence anglep y p p g g g

Shock Deformation of the S oc e o o o erear surface

Proton accelerated in the local target normal direction

Large diverg.Ring-likeRing like

Sh k d l d S fShock modulated SurfaceProton focusing and defocusing locally

Burst-like

locally

Physics of Plasmas 13, 104507 (2006)

Ion Acceleration in the Phase Stable Acceleration RegimeAcceleration Regime

0 16 t=18TPhase space (x~px)

0.12

0.16 t 18TL

p x

AA

0.08BA

■P t

1050 1060100x/λLB

■Protons are:Bunched by Ex2

Debunched by EDebunched by Ex1 .

■Phase Oscillations!

// 04 ~ ( / ) ~e L LE en d v B c Eπ= ×

( / )( / )d λ54

■Phase Oscillations!0( / )( / ) ~c L Ln n d aλ

1D simulation results at t=200 TLa=5, n0/nc=10,

L=0 2λ τ=100 TL 0.2λ, τ 100 TL

(a) Phase space of electrons (b) Phase space distribution of protons

0/ 2 / 4%r rw w pξΔ = Ω <

(a) Phase space of electrons. (b) Phase space distribution of protons.

(c) Electrons and protons density profiles (d) Energy spectrum of protons(c) Electrons and protons density profiles (d) Energy spectrum of protons

X. Q. Yan et al., PRL 100, 135003 (2008).

Stable acceleration in 3D t ith d f d t tgeometry with a deformed target

M. Chen et al., PRL 103, 024801(2009)WG6 TH am, M. Chen

Electrons protons

Flat targettarget

RPA+Laser wakefield acceleration

t i h f il

L.L. Yu et al., NJP 12 (2010) 045021B.F. Shen et al., PRST (2009)

proton-rich foil

d d (Z/A 1/3)

Preaccel.－trapping－further accel.

CP/LP Laser

underdense gas (Z/A=1/3)

◆ Protons in the high density foil can be pre accelerated to

Two conditions:

◆ Protons in the high-density foil can be pre-accelerated tothe GeV level in the RPA regime.

◆ The laser pulse can obviously transmit the overdense foil◆ The laser pulse can obviously transmit the overdense foil to generate wakefields in the underdense plasma.

Above 60 GeV proton beam accelerated in less than 1mmaccelerated in less than 1mm

,max ~ 28.92 /

69 6G Vz eE m c e

W E L

ωAbout 10% of protons are trapped and accelerated to

max ,max ~ 69.6GeVz accW eE L=over 60GeV

Protons in the complex target can be accelerated to energies more than three times, and the energy spread halved, that from the simple double layer target.

W Sh t l P P2009Wang,  Shen et al., PoP2009

a=30

Heavy ions can be efficiently accelerated with electrostatic shockwith electrostatic shock

Foil made of light ionsLaser pulse Foil made of light ions, or protons

Microstructure  made of heavy ions, ex. carbon.

1018 -1019 W/cm2

0.08

0.12

0.08

0.12

0.08

0.12 b)

mic

t=32T 0.06

0.09

0.06

0.09

t=20T0

c)t=32T0

on Laser a=6

0 00

0.04

0 00

0.04

0 00

0.04t=20T0

t=24T0

p x / m t 32T0

0.030.03 t=24T0

N i Laser a 6

Foil 2μmCarbon layer 35 nm

15.5 15.7 16.0 16.2 16.50.00

15.5 15.7 16.0 16.2 16.50.00

15.5 15.7 16.0 16.2 16.50.00

x / λ0

0 20 40 600.00

0 20 40 600 20 40 600.00

ε x (MeV)

phase space of heavy ions  Corresponding energy 

60

p ase space o ea y o sat different time

o espo d g e e gyspectrum 

Liangliang Ji, Baifei Shen et al., Phys. Rev. Lett., 101, 164802 (2008)

Concluding remarks

The Asian community on laser plasma acceleration is growing both in theory/simulation and experiments. A few more new laser facilities are planned or under constructions.

There have been quite a few collaborations in experiments between some labs/groups.

Potential applications of laser-driven particle beams and radiation sources are expected to be significantly pursued among Asian research groups in the future.

Thank you for your attention!y y