Relativistic and charge-displacement self-channeling of intense short-duration laser pulses in plasmas

Numerical solutions are given for the two-dimensional axisymmetric problem of selffocusing of powerful short-duration circularly polarized laser pulses in both initially homogeneous plasmas and static preformed plasma columns. These solutions account for (a) diffraction, (p) refraction arising from variations in the refractive index due to the spatial profile of the electron density distribution, (Y) the relativistic electronic mass shift, and (6) transverse ponderomotively driven charge-displacement. The most important spatial modes of propagation corresponding to the combined action of both the relativistic and charge-displacement mechanisms are described. The dynamics lead to the formation of stable confined modes of propagation having paraxially localized regions of high intensity and corresponding paraxially situated cavitated channels in the electron density. It is further demonstrated that the dynamical solutions of the propagation tend asymptotically to the lowest eigenmodes of the governing nonlinear Schrodinger equation. Finally, the calculations reveal that the relativistic mechanism promotes the initial concentration of the radiative energy and that the subsequent chargedisplacement stabilizes this confinement. The expression for the power threshold of the relativistic and charge-displacement self-channeling is also established.