Ultra-short high-power lasers can deliver extreme light intensities ($\ge {10}^{20}$ W/cm² and $\le 30\hspace{0.17em}\mathrm{f}$s) and drive large amplitude Surface Plasma Wave (SPW) at over-dense plasma surface. The resulting current of energetic electron has great interest for applications, potentially scaling with the laser amplitude, provided that the laser–plasma transfer to the accelerated particles mediated by SPW is still efficient at ultra-high intensity. By means of particle-in-cell simulations, we identify the best condition for SPW excitation and show a strong correlation between the optimum surface plasma wave excitation angle and the laser's angle of incidence that optimize the electron acceleration along the plasma surface. We also discuss how plasma density and plasma surface shape can be adjusted in order to push to higher laser intensity the limit of surface plasma wave excitation. Our results open the way to new experiments on forthcoming multi-petawatt laser systems.

中文翻译：

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超高强度区表面等离子体波激发的关键参数

超短高功率激光器可以提供极高的光强度（$\ge {10}^{20}$ W/cm ²和$\le 30\hspace{0.17em}\mathrm{F}$s) 并在过密的等离子体表面驱动大振幅表面等离子体波 (SPW)。所产生的高能电子电流对应用具有极大的兴趣，可能会随着激光幅度的变化而变化，前提是激光 - 等离子体转移到由 SPW 介导的加速粒子在超高强度下仍然有效。通过细胞内粒子模拟，我们确定了 SPW 激发的最佳条件，并显示了最佳表面等离子体波激发角与激光入射角之间的强相关性，从而优化了沿等离子体表面的电子加速度。我们还讨论了如何调整等离子体密度和等离子体表面形状，以将表面等离子体波激发的极限推向更高的激光强度。