Collisional and collective effects in two dimensional model for fast-electron transport in refluxing regime

The relativistic laser-driven electron transport in partially or fully ionized matter has been investigated in many recent experiments. The high laser intensity achievable today (up to 1020 W/cm2) allows to generate electron current density above 1011 A/cm2. In this regime, electromagnetic effects start to be dominant over collisional ones. In this context, we have developed a simple 2D model for the fast electron transport accounting for (1) electric effects on the electron penetration range and (2) the electron refluxing in thin foils. We compare our model with those existing in literature and with some recent experimental results on fast electron transport in matter. The model predicts a maximum value for the electron penetration range in the region where the collisional and the resistive effects are comparable.