Propagation of radius-tailored laser pulses over extended distances in a uniform plasma*

A Maxwell-fluid model is described, which allows simulation of laser pulses over extended distances (multiple diffraction lengths) in an underdense plasma. This model is used to simulate radius-tailored laser pulses, which can propagate over such distances with minimal distortion in a uniform plasma. Theoretical model equations governing the choice of radius tailoring are also given. A radius-tailored pulse has constant power approximately equal to the critical power for relativistic guiding over the length of the pulse and a spot size at focus that varies over the length of the pulse. A laser pulse configuration of this type can be constructed from a series of ultrashort Gaussian pulses.