Understanding the complex plasma dynamics in ultra-intense relativistic laser-solid interactions is of fundamental importance for applications of laser-plasma-based particle accelerators,the creation of high-energy-de...Understanding the complex plasma dynamics in ultra-intense relativistic laser-solid interactions is of fundamental importance for applications of laser-plasma-based particle accelerators,the creation of high-energy-density matter,understanding planetary science,and laser-driven fusion energy.However,experimental efforts in this regime have been limited by the lack of accessibility of over-critical densities and the poor spatiotemporal resolution of conventional diagnostics.Over the last decade,the advent of femtosecond brilliant hard X-ray free-electron lasers(XFELs)has opened new horizons to overcome these limitations.Here,for the first time,we present full-scale spatiotemporal measurements of solid-density plasma dynamics,including preplasma generation with tens of nanometer scale length driven by the leading edge of a relativistic laser pulse,ultrafast heating and ionization at the main pulse arrival,the laser-driven blast wave,and transient surface return current-induced compression dynamics up to hundreds of picoseconds after interaction.These observations are enabled by utilizing a novel combination of advanced X-ray diagnostics including small-angle X-ray scattering,resonant X-ray emission spectroscopy,and propagation-based X-ray phase-contrast imaging simultaneously at the European XFEL-HED beamline station.展开更多
In the laser plasma interaction of quantum electrodynamics(QED)-dominated regime,γ-rays are generated due to synchrotron radiation from high-energy electrons traveling in a strong background electromagnetic field.Wit...In the laser plasma interaction of quantum electrodynamics(QED)-dominated regime,γ-rays are generated due to synchrotron radiation from high-energy electrons traveling in a strong background electromagnetic field.With the aid of2 D particle-in-cell code including QED physics,we investigate the preplasma effect on theγ-ray generation during the interaction between an ultraintense laser pulse and solid targets.We found that with the increasing preplasma scale length,theγ-ray emission is enhanced significantly and finally reaches a steady state.Meanwhile,theγ-ray beam becomes collimated.This shows that,in some cases,the preplasmas will be piled up acting as a plasma mirror in the underdense preplasma region,where theγ-rays are produced by the collision between the forward electrons and the reflected laser fields from the piled plasma.The piled plasma plays the same role as the usual reflection mirror made from a solid target.Thus,a single solid target with proper scale length preplasma can serve as a manufactural and robustγ-ray source.展开更多
基金partially supported by the Helmholtz Imaging platform through the project“SmartPhase.”。
文摘Understanding the complex plasma dynamics in ultra-intense relativistic laser-solid interactions is of fundamental importance for applications of laser-plasma-based particle accelerators,the creation of high-energy-density matter,understanding planetary science,and laser-driven fusion energy.However,experimental efforts in this regime have been limited by the lack of accessibility of over-critical densities and the poor spatiotemporal resolution of conventional diagnostics.Over the last decade,the advent of femtosecond brilliant hard X-ray free-electron lasers(XFELs)has opened new horizons to overcome these limitations.Here,for the first time,we present full-scale spatiotemporal measurements of solid-density plasma dynamics,including preplasma generation with tens of nanometer scale length driven by the leading edge of a relativistic laser pulse,ultrafast heating and ionization at the main pulse arrival,the laser-driven blast wave,and transient surface return current-induced compression dynamics up to hundreds of picoseconds after interaction.These observations are enabled by utilizing a novel combination of advanced X-ray diagnostics including small-angle X-ray scattering,resonant X-ray emission spectroscopy,and propagation-based X-ray phase-contrast imaging simultaneously at the European XFEL-HED beamline station.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB16000000)the National Natural Science Foundation of China(Nos.11775223,11375197,11605200,and 11275202)+2 种基金the National Key Program for S&T Research and Development(No.2018YFA0404804)the Science Challenge Project(No.TZ2016005)the Open Fund of the State Key Laboratory of High Field Laser Physics(SIOM)。
文摘In the laser plasma interaction of quantum electrodynamics(QED)-dominated regime,γ-rays are generated due to synchrotron radiation from high-energy electrons traveling in a strong background electromagnetic field.With the aid of2 D particle-in-cell code including QED physics,we investigate the preplasma effect on theγ-ray generation during the interaction between an ultraintense laser pulse and solid targets.We found that with the increasing preplasma scale length,theγ-ray emission is enhanced significantly and finally reaches a steady state.Meanwhile,theγ-ray beam becomes collimated.This shows that,in some cases,the preplasmas will be piled up acting as a plasma mirror in the underdense preplasma region,where theγ-rays are produced by the collision between the forward electrons and the reflected laser fields from the piled plasma.The piled plasma plays the same role as the usual reflection mirror made from a solid target.Thus,a single solid target with proper scale length preplasma can serve as a manufactural and robustγ-ray source.
