Figure 4
From: Enhancing laser-driven proton acceleration by using micro-pillar arrays at high drive energy
(a) and (b) The electric field of the laser propagates between the micro-pillars in the PIC simulation (field strength in arbitrary color scale). Electrons heated up by the laser expand into the interstices. (c) and (d) The numerical calculation provides a spatial distribution of the electron density \(({n}_{{e}^{-}})\), normalized to the critical density (n c ) value below which laser propagation is possible (dark blue regions). All plots correspond to the time when the laser intensity reaches half its maximum for two different laser strength parameters a o of 0.24 (left-hand panels) and 1.2 (right-hand panels).
