Hydrodynamic approach to the interaction of a relativistic ultrashort laser pulse with an underdense plasma - art. no. 056409

The interaction of an ultrashort, high peak power laser pulse with an under dense plasma is investigated within a physical model based on the three-dim ensional cold hydrodynamic approach, which allows one to study the dynamics of the laser pulse and of the generated wakefields self-consistently, in t he fully relativistic, strongly nonlinear regime. Our model is developed wi th the aim of describing very short laser pulses (with l(o)<<lambda>(p) and l(o)<<l(perpendicular to) where l(o), l(perpendicular to), lambda (p) are the pulse length, its transverse scale, and the plasma wavelength, respecti vely) down to single cycle radiation wave packets, which have become availa ble with the recent progress in laser technology. The space-time structure and the evolution of large quasistatic electric and magnetic fields are stu died, together with the pulse dynamics, by the direct numerical integration of the relativistic fluid and field equations, within the extended paraxia l approximation.