Accelerated dense ion filament formed by ultra intense laser in plasma slab

The ion acceleration is studied with 3D and 2D PIC simulations of the intense laser pulse interaction with the underdense plasma slab. The simulations reveal the forward acceleration of ions at the rear plasma-vacuum interface. A novel mechanism of the ion acceleration is found. Efficient ion acceleration occurs when an intense quasistatic magnetic field is generated at the rear side of the plasma slab. The magnetic field pressure pushes electrons inside the slab shifting them with respect to the plasma ions. As a result large-scale regions of non-compensated positive electric charge are formed. These regions act as an accelerator and a collimator for the ions from the dense plasma filament formed inside the self-focusing channel.