Generation of self-generated annular magnetic fields at the rear side of a solid target driven by relativistic laser pulse is investigated by using theoretical analysis and particle-in-cell simulations.The spatial str...Generation of self-generated annular magnetic fields at the rear side of a solid target driven by relativistic laser pulse is investigated by using theoretical analysis and particle-in-cell simulations.The spatial strength distribution of magnetic fields can be accurately predicted by calculating the net flow caused by the superposition of source flow and return flow of hot electrons.The theoretical model established shows good agreement with the simulation results,indicating that the magnetic-field strength scales positively to the temperature of hot electrons.This provides us a way to improve the magnetic-field generation by using a micro-structured plasma grating in front of the solid target.Compared with that for a common flat target,hot electrons can be effectively heated with the well-designed grating size,leading to a stronger magnetic field.The spatial distribution of magnetic fields can be modulated by optimizing the grating period and height as well as the incident angle of the laser pulse.展开更多
Relativistic femtosecond mid-infrared pulses can be generated efficiently by laser interaction with near-criticaldensity plasmas.It is found theoretically and numerically that the radiation pressure of a circularly po...Relativistic femtosecond mid-infrared pulses can be generated efficiently by laser interaction with near-criticaldensity plasmas.It is found theoretically and numerically that the radiation pressure of a circularly polarized laser pulse first compresses the plasma electrons to form a dense flying mirror with a relativistic high speed.The pulse reflected by the mirror is red-shifted to the mid-infrared range.Full three-dimensional simulations demonstrate that the central wavelength of the mid-infrared pulse is tunable from 3µm to 14µm,and the laser energy conversion efficiency can reach as high as 13%.With a 0.5–10 PW incident laser pulse,the generated mid-infrared pulse reaches a peak power of 10–180 TW,which is interesting for various applications in ultrafast and high-field sciences.展开更多
The Righi±Leduc heat flux generated by the self-generated magnetic field in the ablative Rayleigh±Taylor instability driven by a laser irradiating thin targets is studied through two-dimensional extended-mag...The Righi±Leduc heat flux generated by the self-generated magnetic field in the ablative Rayleigh±Taylor instability driven by a laser irradiating thin targets is studied through two-dimensional extended-magnetohydrodynamic simulations.The perturbation structure gets into a low magnetization state though the peak strength of the self-generated magnetic field could reach hundreds of teslas.The Righi±Leduc effect plays an essential impact both in the linear and nonlinear stages,and it deflects the total heat flux towards the spike base.Compared to the case without the self-generated magnetic field included,less heat flux is concentrated at the spike tip,finally mitigating the ablative stabilization and leading to an increase in the velocity of the spike tip.It is shown that the linear growth rate is increased by about 10%and the amplitude during the nonlinear stage is increased by even more than 10%due to the feedback of the magnetic field,respectively.Our results reveal the importance of Righi±Leduc heat flux to the growth of the instability and promote deep understanding of the instability evolution together with the self-generated magnetic field,especially during the acceleration stage in inertial confinement fusion.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12175310,12305268,and U2241281)the Natural Science Foundation of Hunan Province(Grant Nos.2024JJ6184,2022JJ20042,and 2021JJ40653)the Scientific Research Foundation of Hunan Provincial Education Department(Grant Nos.22B0655 and 22A0435)。
文摘Generation of self-generated annular magnetic fields at the rear side of a solid target driven by relativistic laser pulse is investigated by using theoretical analysis and particle-in-cell simulations.The spatial strength distribution of magnetic fields can be accurately predicted by calculating the net flow caused by the superposition of source flow and return flow of hot electrons.The theoretical model established shows good agreement with the simulation results,indicating that the magnetic-field strength scales positively to the temperature of hot electrons.This provides us a way to improve the magnetic-field generation by using a micro-structured plasma grating in front of the solid target.Compared with that for a common flat target,hot electrons can be effectively heated with the well-designed grating size,leading to a stronger magnetic field.The spatial distribution of magnetic fields can be modulated by optimizing the grating period and height as well as the incident angle of the laser pulse.
基金supported by the National Natural Science Foundation of China(Grant Nos.12375244,12135009,and 12275356)the Hunan Provincial Innovation Foun-dation for Postgraduate(Grant Nos.CX20210062 and CX20230006).
文摘Relativistic femtosecond mid-infrared pulses can be generated efficiently by laser interaction with near-criticaldensity plasmas.It is found theoretically and numerically that the radiation pressure of a circularly polarized laser pulse first compresses the plasma electrons to form a dense flying mirror with a relativistic high speed.The pulse reflected by the mirror is red-shifted to the mid-infrared range.Full three-dimensional simulations demonstrate that the central wavelength of the mid-infrared pulse is tunable from 3µm to 14µm,and the laser energy conversion efficiency can reach as high as 13%.With a 0.5–10 PW incident laser pulse,the generated mid-infrared pulse reaches a peak power of 10–180 TW,which is interesting for various applications in ultrafast and high-field sciences.
基金supported by the National Natural Science Foundation of China(Grant Nos.12175309,11975308,12005297 and 12275356)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA25050200 and XDA25010100)+2 种基金Xiao-Hu Yang acknowledgesfinancial support from the Fund for NUDT Young Innovator Awards(Grant No.20180104)the Defense Industrial Technology Development Program(Grant No.JCKYS2023212807)Guo-Bo Zhang acknowledgesfinancial support from the Fund for the Research Project of NUDT(Grant No.ZK21-12)。
文摘The Righi±Leduc heat flux generated by the self-generated magnetic field in the ablative Rayleigh±Taylor instability driven by a laser irradiating thin targets is studied through two-dimensional extended-magnetohydrodynamic simulations.The perturbation structure gets into a low magnetization state though the peak strength of the self-generated magnetic field could reach hundreds of teslas.The Righi±Leduc effect plays an essential impact both in the linear and nonlinear stages,and it deflects the total heat flux towards the spike base.Compared to the case without the self-generated magnetic field included,less heat flux is concentrated at the spike tip,finally mitigating the ablative stabilization and leading to an increase in the velocity of the spike tip.It is shown that the linear growth rate is increased by about 10%and the amplitude during the nonlinear stage is increased by even more than 10%due to the feedback of the magnetic field,respectively.Our results reveal the importance of Righi±Leduc heat flux to the growth of the instability and promote deep understanding of the instability evolution together with the self-generated magnetic field,especially during the acceleration stage in inertial confinement fusion.
