Key parameters for surface plasma wave excitation in the ultra-high intensity regime

Ultra-short high-power lasers can deliver extreme light intensities ($\ge 10^{20}$ W/cm$^2$ and $\leq 30 f$s) 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 laser-plasma transfer to accelerated particles mediated by SPW is still efficient ultra-high intensity. By mean Particle-in-Cell simulations, we identify best condition excitation show a strong correlation between optimum angle laser's incidence that optimize acceleration along We also discuss how density surface shape be adjusted in order push higher intensity limit excitation. Our results open way new experiments on forthcoming multi-petawatt systems.