Dudnikova_Galina

Report
SHOCK WAVE PARTICLE
ACCELERATION in LASERPLASMA
INTERACTION
G.I.Dudnikova, T.V.Leseykina
ICT SBRAS
SCT-2012, Novosibirsk, June 8, 2012
Introduction & Motivation
 The progress in laser technology has led to light sources delivering pulses
of femtosecond duration and focused intensities up to 1022 W/cm2
NOVA Laser
(1999, LLNL, petawatt)
HERCULES (CUOS),
Table Top Petawatt
Introduction & Motivation
 Experiments carried out in recent years on the laser-plasma interaction
show the possibility of ions acceleration to high energy (tens of MeV)
 Compact and affordable ion accelerator based on laser produced plasmas
have potential applications in many fields of science and medicine
(radiography, isotopes generation, cancer therapy, inertial fusion).
 Two more studied mechanism of ion
acceleration are TNSA (60MeV,
energy spread 20%), RPA ( 30 Mev, 50%, ).
TNSA accelerating ions by
ultra-intense laser pulses
 The light pressure, P=2I/c, from Gigabar to Terabar may compress plasma
and generate shock waves that lead to acceleration of ions due to reflection by
shock front (monoenergetic component in ion spectra are produced )
Set -up
Foil:
full ionized H plasma
Foil size:
3-20 λ
Foil density:
2-100 n*,
Laser pulse:
circular polarized
Amplitude a:
2-50
a=eE/ mcɷ
a=sqrt(I/1.35 1018 Wcm -2 (λ/µm) 2)
n*= 1.1 10^21 cm^-3, λ=0.8 µm
4 λ< R < 10 λ
5 λ< L < 400 λ
5 λ< X1< 10 λ
2 λ< X2 < 5λ
2 λ< X1 < 10 λ
HERCULES (MI), ATF BNL (NY), Sokol-P (Snezhinsk, Russia)
Numerical Model
Numerical modelling is carried out on the basis of code UMKA2D3V*, allowing to carry out
calculations of interaction of laser radiation with plasma of any complex structure and to choose
type of boundary conditions for an electromagnetic field (reflection, absorption, periodic
conditions). The effective algorithm of parallel calculations is created, and its realization on
multiprocessing complexes MBC-15000 (Moscow) is carried out. At the decision it was used 100150 processors of complex MBC-15000, calculation up to the moment of time to the equal 400
laser periods has occupied approximately 5000 hours of processor time.
* Vshivkov V.A., Dudnikova G.I. Comput. Technol., 2001.
Channel & caviton formation
Plasma formations observed in experiment (ATF BNL) and simulated (bottom row)
shadowgram and a simulated plasma profile for case filamentation and solitons for ne<n*,
postsolitons for ne<n*; ne=2n*; ne=2.5 n*
*I. V. Pogorelsky, et.al, Proceedings of IPAC’10, Kyoto, Japan, 2010.
Hole-boring and shock formation
V=0.06 c
Vhb= sqrt((1+k) I / ƍc)
Cs=sqrt(kTe /mi)
Te=mc2sqrt(1+a2/2)
M=1.3
Ion phase space
Ion trajectories
Distribution function
Palmer Charlotte A. J.; Dover N. P.; Dudnikova G. I., et. al
Phys. Rev. Lett. 106, 014801 (2011)
Flat pulse
R-T instability
Ion density
Proton energy spectra
Ion energy phase space
T.C.Liu, G. Dudnikova, et.al, Phys.Plasma, 18, 2011
Plasma density temporal evolution. a=32, n=169 n*, d=0.25 λ
I=1.4 10 21W/cm2, n=1.9 10 23 cm-3, d=0.25 µm
a=32
Energy spectrum
Summary
• Laser acceleration is potentially an affordable alternative to traditional
cyclotron acceleration. Intense, high quality ion beams driven by relativistic
laser plasma - the next generation ion accelerators.
• Shock-like acceleration due to the ion reflection at the front of the
compressed layer in the plasma lets to obtain the quasi-monoenergetic ion
bunch.
• In realistic geometries there are two independent obstacles to sustain
quasi-mono-energetic regime of acceleration:
Rayleigh-Taylor instability of plasma sheet
lateral expansion of plasma

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