The process of high energy electron acceleration along the surface of grating targets(GTs)that were irradiated by a relativistic,high-contrast laser pulse at an intensity I=2.5×10^20 W/cm^2 was studied.Our experi...The process of high energy electron acceleration along the surface of grating targets(GTs)that were irradiated by a relativistic,high-contrast laser pulse at an intensity I=2.5×10^20 W/cm^2 was studied.Our experimental results demonstrate that for a GT with a periodicity twice the laser wavelength,the surface electron flux is more intense for a laser incidence angle that is larger compared to the resonance angle predicted by the linear model.An electron beam with a peak charge of∼2.7 nC/sr,for electrons with energies>1.5 MeV,was measured.Numerical simulations carried out with parameters similar to the experimental conditions also show an enhanced electron flux at higher incidence angles depending on the preplasma scale length.A theoretical model that includes ponderomotive effects with more realistic initial preplasma conditions suggests that the laser-driven intensity and preformed plasma scale length are important for the acceleration process.The predictions closely match the experimental and computational results.展开更多
We demonstrated experimentally the formation of monoenergetic beams of accelerated electrons by focusing femtosecond laser radiation with an intensity of 2×1017W/cm2onto the edge of an aluminum foil.The electrons...We demonstrated experimentally the formation of monoenergetic beams of accelerated electrons by focusing femtosecond laser radiation with an intensity of 2×1017W/cm2onto the edge of an aluminum foil.The electrons had energy distributions peaking in the 0.2–0.8 MeV range with energy spread less than 20%.The acceleration mechanism related to the generation of a plasma wave as a result of self-modulation instability of a laser pulse in a dense plasma formed by a prepulse(arriving 12 ns before the main pulse)is considered.One-dimensional and two-dimensional Particle in Cell(PIC)simulations of the laser–plasma interaction showed that effective excitation of a plasma wave as well as trapping and acceleration of an electron beam with an energy on the order of 1 MeV may occur in the presence of sharp gradients in plasma density and in the temporal shape of the pulse.展开更多
基金Computational support and infrastructure were provided by the Centre for Information and Media Technology(ZIM)of the University of Dusseldorf(Germany).
文摘The process of high energy electron acceleration along the surface of grating targets(GTs)that were irradiated by a relativistic,high-contrast laser pulse at an intensity I=2.5×10^20 W/cm^2 was studied.Our experimental results demonstrate that for a GT with a periodicity twice the laser wavelength,the surface electron flux is more intense for a laser incidence angle that is larger compared to the resonance angle predicted by the linear model.An electron beam with a peak charge of∼2.7 nC/sr,for electrons with energies>1.5 MeV,was measured.Numerical simulations carried out with parameters similar to the experimental conditions also show an enhanced electron flux at higher incidence angles depending on the preplasma scale length.A theoretical model that includes ponderomotive effects with more realistic initial preplasma conditions suggests that the laser-driven intensity and preformed plasma scale length are important for the acceleration process.The predictions closely match the experimental and computational results.
基金supported by the programme ‘Extreme Light Fields and Their Applications’ of the Presidium of the Russian Academy of Sciences
文摘We demonstrated experimentally the formation of monoenergetic beams of accelerated electrons by focusing femtosecond laser radiation with an intensity of 2×1017W/cm2onto the edge of an aluminum foil.The electrons had energy distributions peaking in the 0.2–0.8 MeV range with energy spread less than 20%.The acceleration mechanism related to the generation of a plasma wave as a result of self-modulation instability of a laser pulse in a dense plasma formed by a prepulse(arriving 12 ns before the main pulse)is considered.One-dimensional and two-dimensional Particle in Cell(PIC)simulations of the laser–plasma interaction showed that effective excitation of a plasma wave as well as trapping and acceleration of an electron beam with an energy on the order of 1 MeV may occur in the presence of sharp gradients in plasma density and in the temporal shape of the pulse.
