Nonlinear photon z-pinching in filamentary self-compression

The paper discusses on-axis self-compression as arising from a self-induced spatial contraction of the pulsed laser beam, with only negligible longitudinal energy exchange and conventional pulse shaping action. The mechanism behind the novel compression scheme is found to show a resemblance with methods for compressing electric currents in so-called z-pinch discharges. These high-current discharges show some remarkable parallels to the nonlinear optical scenario of filamentary propagation. These include a nonlinear Schrodinger equation for the magnetic field, the formation of plasma filaments due to spatial break-up, and a self-induced pinching mechanism.