The impact of electron heating on laser-plasma ion acceleration mechanisms

Intense laser-plasma interactions offer the possibility of producing short high-energy ion beams for a wide range of applications. We have performed particle-in-cell simulations of laser-driven ion acceleration for a large set of parameters. We show that the ion acceleration mechanisms and the spectral shape of the produced beams can be controlled by the laser electron heating. In regimes of weak laser absorption, direct piston acceleration (hole boring) is dominant and no shock is formed, whereas when the electron temperature increases there is competition between shock acceleration and TNSA. We will discuss how the simulation dimensionality, target density, laser incidence angle and polarization control the electron heating and thereby the properties of the accelerated ion beams.