A two-dimensional electromagnetic field algorithm for high-intensity laser–target interactions. The interaction of high-intensity ultrashort pulse lasers with solid targets is modeled via a 2D2V relativistic electromagnetic particle-in-cell code. In order to obtain a stable numerical solution of the field equations, the current density from the particle equations is written in a form with the electric field factored out and inserted into the Maxwell equations. The resulting system is very robust with excellent energy conserving properties. This technique is applicable to a wide range of conditions: from non-relativistic to the highly relativistic regime and for both underdense and highly overdense plasmas.