Density modification and energetic ion production at relativistic self-focusing of laser beams in plasmas

Abstract

A two-dimensional time-dependent laser plasma interaction code is described and used to model the interaction between a 5 psec Nd glass laser pulse of peak power 1013 W and a 35 times ionized tin target. Parameters are chosen so that relativistic self-focusing down to a diameter of the order of the wavelength of the laser light is observed in a distance comparable to the half intensity vacuum beam diameter. At later times strong modification of the plasma density by the nonlinear force is observed. The combination of relativistic self-focusing and axial nonlinear force results in the acceleration of tin ions to a maximum energy of 5 GeV, in agreement with previous approximate calculations.