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| 1 | Absolute instability modes due to rescattering of stimulated Raman scattering in a large nonuniform plasma显示文摘Absolute instability modes due to secondary scattering of stimulated Raman scattering (SRS) in a large nonuniform plasma are studied theoretically and numerically. The backscattered light of convective SRS can be considered as a pump light with a finite bandwidth. The different frequency components of the backscattered light can be coupled to develop absolute SRS instability near their quarter-critical densities via rescattering process. The absolute SRS mode develops a Langmuir wave with a high phase velocity of about c/■ with c the light speed in vacuum. Given that most electrons are at low velocities in the linear stage, the absolute SRS mode grows with very weak Landau damping. When the interaction evolves into the nonlinear regime, the Langmuir wave can heat abundant electrons up to a few hundred ke V via the SRS rescattering. Our theoretical model is validated by particle-in-cell simulations. The absolute instabilities may play a considerable role in the experiments of inertial confinement fusion. | Yao Zhao Zhengming Sheng Suming Weng Shengzhe Ji Jianqiang Zhu | 2019 | High Power Laser Science and Engineering2019，7，1： | 2 |
| 2 | Stimulated Raman scattering excited by incoherent light in plasma显示文摘Stimulated Raman scattering(SRS)excited by incoherent light is studied via particle-in-cell simulations.It is shown that a large bandwidth of incoherent light can reduce the growth of SRS and electron heating considerably in the linear stage.However,different components of the incoherent light can be coupled by the Langmuir waves,so that stimulated Raman backward scattering can develop.When the bandwidth of incoherent light is larger than the Langmuir wave frequency,forward SRS can be seeded between different components of the incoherent light.The incoherent light can only increase the time duration for nonlinear saturation but cannot diminish the saturation level obviously. | Yao Zhao Suming Weng Min Chen Jun Zheng Hongbin Zhuo Zhengming Sheng | 2017 | Matter and Radiation at Extremes2017，2，4： | 1 |
| 3 | Magnetic field annihilation and reconnection driven by femtosecond lasers in inhomogeneous plasma显示文摘The process of fast magnetic reconnection driven by intense ultra-short laser pulses in underdense plasma is investigated by particle-in-cell simulations. In the wakefield of such laser pulses, quasi-static magnetic fields at a few mega-Gauss are generated due to nonvanishing cross product ▽(n/) × p. Excited in an inhomogeneous plasma of decreasing density, the quasi-static magnetic field structure is shown to drift quickly both in lateral and longitudinal directions. When two parallel-propagating laser pulses with close focal spot separation are used, such field drifts can develop into magnetic reconnection(annihilation) in their overlapping region, resulting in the conversion of magnetic energy to kinetic energy of particles. The reconnection rate is found to be much higher than the value obtained in the Hall magnetic reconnection model. Our work proposes a potential way to study magnetic reconnection-related physics with short-pulse lasers of terawatt peak power only. | YouYuan Wang FeiYu Li Min Chen SuMing Weng QuanMing Lu QuanLi Dong ZhengMing Sheng Jie Zhang | 2017 | Science China(Physics,Mechanics & Astronomy)2017，60，11： | 0 |
| 4 | Nonlocal thermal transport in magnetized plasma along different directions显示文摘Nonlocal thermal transport in magnetized plasmas is studied theoretically and numerically with the Vlasov–Fokker–Planck(VFP)model,in which the magnetic field has nonzero components both perpendicular to and along the temperature gradient.Nonlocal heat transport is found in both the longitudinal and transverse directions,provided the temperature gradients are sufficiently large.The magnetic field tends to reduce the nonlocality of the thermal transport in the direction perpendicular to the magnetic field,i.e.,the difference between the heat fluxes predicted by the Braginskii theory and the VFP simulation decreases with increasing magnetic field strength.When the initial temperature gradient is steep,the nonlocal heat flux depends not only on the present temperature profile,but also on its time history.Moreover,the contribution of high-order terms in the spherical harmonic expansion of the electron distribution function becomes important for a magnetized plasma,in particular for thermal transport in the direction perpendicular to the temperature gradient. | Hanzhi Zhao Zhengming Sheng Suming Weng | 2022 | Matter and Radiation at Extremes2022，7，4： | 0 |
| 5 | Stimulated Raman scattering in a non-eigenmode regime显示文摘Stimulated Raman scattering(SRS)in plasma in a non-eigenmode regime is studied theoretically and numerically.Different from normal SRS with the eigen electrostatic mode excited,the non-eigenmode SRS is developed at plasma density ne>0.25nc when the laser amplitude is larger than a certain threshold.To satisfy the phase-matching conditions of frequency and wavenumber,the excited electrostatic mode has a constant frequency around half of the incident light frequency ω0/2,which is no longer the eigenmode of electron plasma wave ωpe.Both the scattered light and the electrostatic wave are trapped in plasma with their group velocities being zero.Super-hot electrons are produced by the non-eigen electrostatic wave.Our theoretical model is validated by particle-in-cell simulations.The SRS driven in this non-eigenmode regime is an important laser energy loss mechanism in the laser plasma interactions as long as the laser intensity is higher than 10^15 W/cm^2. | Yao Zhao Suming Weng Zhengming Sheng Jianqiang Zhu | 2020 | High Power Laser Science and Engineering2020，8，2： | 0 |
| 6 | Effects of second-order dispersion of ultrashort laser pulse on stimulated Raman scattering显示文摘The influence of second-order dispersion(SOD)on stimulated Raman scattering(SRS)in the interaction of an ultrashort intense laser with plasma was investigated.More significant backward SRS was observed with the increase of the absolute value of SOD(|ψ2|).The integrated intensity of the scattered light is positively correlated to the driver laser pulse duration.Accompanied by the side SRS,filaments with different angles along the laser propagation direction were observed in the transverse shadowgraph.A model incorporating Landau damping and above-threshold ionization was developed to explain the SOD-dependent angular distribution of the filaments. | Yanqing Deng Dongning Yue Mufei Luo Xu Zhao Yaojun Li Xulei Ge Feng Liu Suming Weng Min Chen Xiaohui Yuan Jie Zhang | 2022 | High Power Laser Science and Engineering2022，10，6： | 0 |
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