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Hot Electron and Pair Production from the Texas Petawatt Laser Irradiating Thick Gold Targets  [PDF]
Devin Taylor,Edison Liang,Taylor Clarke,Alexander Henderson,Petr Chaguine,Xin Wang,Gilliss Dyer,Kristina Serratto,Nathan Riley,Michael Donovan,Todd Ditmire
Physics , 2012, DOI: 10.1016/j.hedp.2013.02.002
Abstract: We present data for relativistic hot electron production by the Texas Petawatt Laser irradiating solid Au targets with thickness between 1 and 4 mm. The experiment was performed at the short focus target chamber TC1 in July 2011, with laser energies around 50 J. We measured hot electron spectra out to 50 MeV which show a narrow peak around 10 - 20 MeV plus high energy exponential tail. The hot electron spectral shape differs from those reported for other PW lasers. We did not observe direct evidence of positron production above background.
About Low Frequency Resonances of Elastic Spheroidal Shells, Irradiating and Establishing by Harmonic and Pulse Signals
International Journal of Theoretical and Mathematical Physics , 2013, DOI: 10.5923/j.ijtmp.20130301.02
Abstract: The done before analysis of the low frequency resonances of the elastic spheroidal bodies, irradiating and establishing by the harmonic signal[1], supplemented with the research of the elastic spheroidal shell, irradiating and establishing by the pulse signal.
Dynamics of the wakefield of a multi-petawatt, femtosecond laser pulse in a configuration with ultrarelativistic electrons  [PDF]
D. Jovanovic,R. Fedele,M. Belic
Physics , 2014, DOI: 10.1209/0295-5075/107/44004
Abstract: The wake field excitation in an unmagnetized plasma by a multi-petawatt, femtosecond, pancake-shaped laser pulse is described both analytically and numerically in the regime with ultrarelativistic electron jitter velocities, when the plasma electrons are almost expelled from the pulse region. This is done, for the ?rst time, in fluid theory. A novel mathematical model is devised that does not break down for very intense pump strengths, in contrast to the standard approach that uses the laser ?eld envelope and the ponderomotive guiding center averaging. This is accomplished by employing a three-timescale description, with the intermediate scale associated with the nonlinear phase of the electromagnetic wave and with the bending of its wave front. The evolution of the pulse and of its electrostatic wake are studied by the numerical solution in a two-dimensional geometry, with the spot diameter \geq 100 microns. It reveals that the optimum initial pulse length needs to be somewhat bigger than 1 micron (1-2 oscillations), as suggested by simple analytical local estimates, because the nonlocal plasma response tends to stretch very short pulses.
Dispersion and localization in structured Rayleigh beams  [PDF]
A. Piccolroaz,A. B. Movchan
Physics , 2014,
Abstract: This paper brings a comparative analysis between dynamic models of couple-stress elastic materials and structured Rayleigh beams on a Winkler foundation. Although physical phenomena have different physical origins, the underlying equations appear to be similar, and hence mathematical models have a lot in common. In the present work, our main focus is on the analysis of dispersive waves, band-gaps and localized waveforms in structured Rayleigh beams. The Rayleigh beam theory includes the effects of rotational inertia which are neglected in the Euler--Bernoulli beam theory. This makes the approach applicable to higher frequency regimes. Special attention is given to waves in pre-stressed Rayleigh beams on elastic foundations.
Isolated intense 38 attosecond pulse generation from the combined laser pulse irradiating the coherent superposition state

Chen Ji-Gen,Yang Yu-Jun,Yu Xu-Ping,He Long-Jun,Xu Yuan-Yuan,

物理学报 , 2011,
Abstract: A scheme to efficiently generate an intense short isolated attosecond pulse is presented by the combined laser pulse irradiating the coherent superposition state.The combined pulse is composed of a multi-cycle 800 nm laser and a 1600 nm one.Compared with the case of the fundamental laser irradiating the ground state,the cutoff position is significantly extended from 70th to 280th harmonic,a broadband supercontinuum spectrum with 108 eV spectral width can be produced which directly generates an isolated 38 a...
Generation of high-energy electron-positron beams in the collision of a laser-accelerated electron beam and a multi-petawatt laser  [PDF]
Mathieu Lobet,Xavier Davoine,Emmanuel d'Humières,Laurent Gremillet
Physics , 2015,
Abstract: Generation of antimatter via the multiphoton Breit-Wheeler process in an all-optical scheme will be made possible on forthcoming high-power laser facilities through the collision of wakefield-accelerated GeV electrons with a counter-propagating laser pulse with $10^{22}$-$10^{23}$ $\mathrm{Wcm}^{-2}$ peak intensity. By means of integrated 3D particle-in-cell simulations, we show that the production of positron beams with 0.1-1 nC total charge, 100-400 MeV mean energy and 0.01-0.1 rad divergence is within the reach of soon-to-be-available laser systems. The variations of the positron beam's properties with respect to the laser parameters are also examined.
Hydrodynamic Implosion Simulation Including Relativistic Effects on Petawatt-Class Pulse Heating  [PDF]
Mitsuru Honda
Physics , 2003, DOI: 10.1143/JJAP.42.5280
Abstract: A spherically symmetric fluid code that includes the relativistic effects of hot electrons has been newly developed. In the present simulations, I attempt to implode a target shell of laser fusion using a nanosecond pulse; then, an additional heating short pulse is injected into the coronal plasma surrounding a highly compressed core. I found that the relativistic effects of hot electrons on electron transport are likely to inhibit the heat flows, and to reduce thermonuclear fusion neutrons significantly. This feature may be important for off-center fast ignition and burn of fusion targets.
Petawatt激光与应用  [PDF]
四川师范大学学报(自然科学版) , 2002,
Abstract: 对Petawatt激光及其应用开发和典型事例作一概要论述
Single X-Ray Attosecond Pulse Generation by Using Combined Pulses Irradiating on a United Two-Atom System
CHEN Ji-Gen,LI Chen,CHI Fang-Ping,YANG Yu-Jun,

中国物理快报 , 2007,
Abstract: A scheme of a single x-ray attosecond pulse generation from a two-atom system exposed to the combined laser pulses is proposed. Our numerical results show that a single x-ray attosecond pulse rather than a train one can be produced by modulation of ionization. Furthermore, when we change the peak intensity Ih of the high-frequency pulse and keep the intensity of the low-frequency pulse constant, we can find that a range of Ih where the intensity of the attosecond pulse is optimal is available, and a explanation by the stimulated property of the recombination is also presented.
An all fiber multi-laser pulse generation system

Lin Hong-Huan,Wang Jian-Jun,Dang Zhao,Zhang Rui,Deng Ying,Xu Dang-Peng,Chen Ji,Wang Chao,Chen De-Huai,

物理学报 , 2010,
Abstract: We demonstrate an all fiber multi-laser pulse generation system that can output broadband chirped pulse, nano-second shaped pulse and narrowband pump pulse for optical parametric chirped pulsed amplifiers system with precise synchronization. Yb~(3+)-doped fiber mode-locked laser and single longitudinal oscillator are used as the optical source for the fiber system. The ultra-short pulse train generated from the mode locked fiber laser was split into two beam-lines and both were chirp-stretched to 0. 9 ns. One of them was directly amplified to a magnitude of 10 μJ to provide the high-energy petawatt laser facility with seed pulse. The other was tailored by a 1.2 nm bandwidth filter to form a 140 ps unit pulse. It was then stacked in a fiber stacker and formed a 2. 3 ns arbitrarily shaped pulse. The shaped pulse was amplified to 10 μJ to provide seed pulse for the peUet compression. Simultaneously, we sampled part of the ultra-short pulse train from the mode locked laser. The sampled pulse train was converted to electrical signal and phase-locked to generate trigger pulse that precisely synchronized with the mode locked pulse for an amplitude modulator. The continuous-wave laser generated from the fiber single longitudinal oscillator was tailed by the amplitude modulator and then amplified to provide seed pulse for the OPCPA system. The output of the fiber system can switch between different kinds of pulses with flexibility according to the physical experimental requirement.
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