A dynamic spatial replenishment scenario for femtosecond pulses propagating in air - A route to optical turbulence?

Recently, the nonlinear Schrödinger equation, extended to include ionization interaction between light and weak plasma, was used to explore numerically the experimentally observed long, filamentary propagation of femtosecond pulses in air. A rather dynamic picture arises in which an initial pulse is formed, absorbed by plasma generation, and subsequently replenished by power from the trailing edge of the pulse. This process, termed dynamic spatial replenishment, can repeat several times and produce long distance propagation for high power input pulses. The onset and recurrence of multiple light filaments during the long-distance propagation of intense femtosecond infrared pulses in air in the simulations resembles the behavior reported experimentally and is shown to share features with strong turbulence in other physical systems. Here, however, space-time collapse events drive the turbulence, and plasma defocusing, not dissipation, is the dominant mechanism regularizing the collapse.