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Xu Y.,East China Normal University | Wang J.,East China Normal University | Qi X.,CAS Lanzhou Institute of Modern Physics | Li M.,East China Normal University | And 3 more authors.
Physics of Plasmas | Year: 2017

By using two-dimensional particle-in-cell simulations, plasma block acceleration via radiation pressure from an ultraintense circularly polarized laser pulse with intensity I ≈ 10 22 W / cm 2 is investigated based on a double-target scheme, in which the targets are composed of a pre-target with a relatively low plasma density and a main target with a high plasma density. It has been demonstrated that an appropriately selected pre-target can help to greatly enhance the charge separation field in the main target, which then leads to generation of a strongly accelerated and well directed plasma block with proton energy in GeV magnitude. This result can have potential applications in the plasma block ignition of proton-born fusion. © 2017 Author(s).


Li A.K.,East China Normal University | Wang J.X.,East China Normal University | Ren N.,East China Normal University | Zhu W.J.,National Key Laboratory of Shock Wave and Detonation Physics | And 5 more authors.
Laser Physics | Year: 2014

In this paper a detailed numerical comparison of the high-harmonic generation (HHG) from free electrons in intense laser fields in both classical and semi-classical frameworks has been presented These two frameworks have been widely used in the literature It has been found that the HHG spectra display distinct quantitative differences for high-energy electrons In some special situations qualitative differences appear Even if the radiation reaction is included in the electron classical dynamics no consistent result can be obtained Hence it should be of critical importance to submit the present HHG theory for high-precision experimental tests which can help us not only to justify the present theories but also to check the QED predictions in the high-intensity regime © 2014 Astro Ltd.


Li A.,East China Normal University | Wang J.,East China Normal University | Ren N.,East China Normal University | Wang P.,Applied Ion Beam Physics Laboratory | And 7 more authors.
Applied Physics B: Lasers and Optics | Year: 2014

When an electron is scattered by a tightly focused laser beam in vacuum, the intensity gradient is a critical factor to influence the electron dynamics. In this paper, we have further investigated its influence upon the electron high-harmonic generation (HHG) by treating the spacial gradient of the laser intensity as a ponderomotive potential. Based upon perturbative quantum electrodynamics calculations, it has been found that the main effect of the intensity gradient is the broadening of the originally line HHG spectra. A one-to-one relationship can be built between the beam width and the corresponding line width. Hence, this finding may provide us a promising way to measure the beam width of intense lasers in experiments. In addition, for a laser pulse, we have also studied the different influences from transverse and longitudinal intensity gradients upon HHG. © 2014, Springer-Verlag Berlin Heidelberg.


Ma Y.,East China Normal University | Wang J.,East China Normal University | Xu X.,East China Normal University | Wei Q.,East China Normal University | And 3 more authors.
Journal of the Physical Society of Japan | Year: 2014

In this work, the one-dimensional incommensurate quantum Frenkel-Kontorova model is investigated using a densitymatrix renormalization group algorithm. Special attention is given to the entanglement and ground-state energy. The energy gap between ground state and the first excited state is also calculated. From all the numerical results, we have observed clear property changes from the pinned state to the sliding state as the amount of quantum fluctuation is increased. However, no expected quantum critical point can be justified by the present data. © 2014 The Physical Society of Japan.


Li A.,East China Normal University | Wang J.,East China Normal University | Ren N.,East China Normal University | Wang P.,Fudan University | And 5 more authors.
Journal of Applied Physics | Year: 2013

In this paper, the spontaneous bremsstrahlung emission from an electron scattered by two fixed nuclei in an intense laser field is investigated in detail based upon the Volkov state and the Dirac-Volkov propagator. It has been found that the fundamental harmonic spectrum from the electron radiation exhibits distinctive fringes, which is dependent not only upon the internucleus distance and orientation but also upon the initial energy of the electron and the laser intensity. By analyzing the differential cross section, we are able to explain these effects in terms of interference among the electron scattering by the nuclei. These results could have promising applications in probing the atomic or molecular dressed potentials in intense laser fields. © 2013 AIP Publishing LLC.


Fang Y.,Zhejiang University | Meng C.,National Key Laboratory of Shock Wave and Detonation Physics | Zhu W.,National Key Laboratory of Shock Wave and Detonation Physics | He D.,University of Sichuan | And 2 more authors.
Journal of Applied Physics | Year: 2013

A series of shock compression experiments on hexagonal α-Ce 3Al have been carried out using a two-stage light gas gun. No phase transition was observed in the recovered sample shock compressed at 23.5 GPa. However, as the shock pressure was increased to 27.3 GPa, a face-centered cubic Ce3Al phase was detected in the samples recovered at ambient conditions. Furthermore, a Ce2Al phase was found in the 37.1 GPa shocked sample with a space group Fd-3m and lattice parameter a 8.26(1) Å. These Ce-based alloys may have potential industrial applications due to the heavy-fermion related properties. © 2013 American Institute of Physics.


Wang H.,University of Sichuan | He D.,University of Sichuan | He D.,Sichuan University | Xu C.,University of Sichuan | And 6 more authors.
Journal of Applied Physics | Year: 2013

We report the preparation of nanostructured diamond-TiC composites with high fracture toughness and high hardness starting from a ball-milled mixture of nano-sized Ti3SiC2 and submicron-sized diamond by simultaneously tuning the pressure-temperature conditions. The phase segregation of Ti3SiC2 at pressure of 5.5 GPa were investigated by X-ray diffraction and high resolution transmission electron microscopy, we found that the Ti3SiC2 could decompose into nanosized TiC and amorphous Ti-Si at 600-700 °C. The subsequent reaction between diamond and Ti-Si led to an amorphous Ti-Si-C matrix in which diamond and TiC crystals are embedded. With a loading force of 98 N, the measured fracture toughness K IC and Vicker's hardness HV of the synthesized composites reach up to 14 MPa m1/2 and 45.5 GPa, respectively. Our results demonstrate that the nanocrystalline/amorphous bonding matrix could largely enhance the toughness of the brittle composites. © 2013 American Institute of Physics.


Wang Q.-W.,University of Sichuan | Li X.-Y.,National Key Laboratory of Shock Wave and Detonation Physics | Lu X.-F.,University of Sichuan | Lu X.-F.,CAS Institute of Theoretical Physics
International Journal of Modern Physics E | Year: 2012

We study the effective mass of nucleon from chiral perturbation theory in the finite chemical potential. By including in the chiral Lagrangian a chemical potential conjugating to the baryon number density, the calculation of integration over meson momentum has to face complex plain which gives the chemical potential dependence of nucleon mass in dense matter. The results indicate that the interaction between nucleons is attractive at first and then repulsive as the chemical potential increases. © 2012 World Scientific Publishing Company.


Li X.,National Key Laboratory of Shock Wave and Detonation Physics | Wang J.,East China Normal University | Zhu W.,National Key Laboratory of Shock Wave and Detonation Physics | Ye Y.,National Key Laboratory of Shock Wave and Detonation Physics | And 2 more authors.
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011

The possibility of enhancing inner-shell x-ray emission, especially Kα emission, by femtosecond-laser irradiation of solid cones instead of foils was investigated theoretically. In a model for hot electron (HE) transport and Kα x-ray generation, Kα emission from laser-irradiated solid cones and foils is investigated. As a complementarity to the model, the contributions from electric and magnetic fields generated by the HE current in solid cones and foils are discussed. The results indicate that the efficiency of HE energy conversion to Kα photons is improved and the optimum HE temperature is increased. © 2011 American Physical Society.


Tian J.-J.,Southwest University of Science and Technology | Tian J.-J.,National Key Laboratory of Shock Wave and Detonation Physics | Gao L.-D.,National Key Laboratory of Shock Wave and Detonation Physics | Liu Y.,National Key Laboratory of Shock Wave and Detonation Physics | And 3 more authors.
Gongneng Cailiao/Journal of Functional Materials | Year: 2013

Al2O3/epoxy composite was prepared by solution process after Al2O3 powder was modified by KH560 coupling agent. The impact of coupling agent on microstructure of composites was studied by FT-IR and SEM. The dielectric properties were measured by 4294A impedance analyzer. It was found that the interfacial of Al2O3 and KH560 forms chemical bonds. The coupling agent improves the interaction between Al2O3 and epoxy. Both the fraction of Al2O3 and KH560 have an important impact on dielectric property. Dielectric permittivity of the composite with treated Al2O3 was higher than that of composite with untreated Al2O3. Besides, the electric field intensity of cathode triple-point junction has been simulated by electrostatic field simulation. The result shows that Al2O3/epoxy composite increases dielectric properties between ceramic and epoxy as well as decreases the electric field intensity of cathode triple-point junction.

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