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