Figure 2

Some results of the PIC simulations. (a) shows the proton spectra normalized to give an approximated estimate of the experimental values in the 2D simulation scan (time selection is explained in Sect. 3) and at 300 fs in the 3D simulation. (b) shows two snapshots of the 3D simulation: in greys, the electron density normalized to \(n_{c}\). At 150 fs the \(B_{z}\) field and some foam electron trajectories in green are visible. At 300 fs the accelerated protons are represented as spheres colored according to their energy \(E_{p}\)