Effects of laser waveform on the generation of fast electrons in laser-solid interactions

In the scheme of fast ignition of inertial confinement fusion, the fuel temperature mainly relies on fast electrons, which act as an energy carrier, transferring the laser energy to the fuel. Both conversion efficiency from the laser to the fast electron and the energy spectrum of the fast electron are essentially important to achieve highly effective heating. In this study, a two-dimensional particle in cell simulation is applied to study the generation of fast electrons from solid-density plasmas with different laser waveforms. The results have shown that the slope of the rising edge has a significant effect on fast electron generation and energy absorption. For the negative skew pulse with a relatively slow rising edge, the J x B mecha-nism can most effectively accelerate the electrons. The overall absorption efficiency of the laser energy is optimized, and the fast electron yield in the middle-and low-energy range is also improved.

Automated summary

In the fast ignition scheme of inertial confinement fusion, the fuel temperature primarily depends on fast electrons, which serve as energy carriers transferring laser energy to the fuel. The conversion efficiency from laser to fast electron and the energy spectrum of fast electrons are crucial for achieving efficient heating. This study utilizes a two-dimensional particle-in-cell simulation to investigate the generation of fast electrons from solid-density plasmas using different laser waveforms.It was found that the slope of the rising edge significantly affects fast electron generation and energy absorption. The J x B mechanism is most effective for accelerating electrons in the case of a negatively skewed pulse with a relatively slow rising edge. The overall absorption efficiency of laser energy is optimized, and the yield of fast electrons in the middle and low-energy range is also improved.