Anderson self-localization of light in pair plasmas

Abstract: We demonstrate that in pair plasma weakly nonlinear electromagnetic waves, $a_0 \leq 1$, experience Anderson self-localization. The beat between the driver and a back-scattered wave creates random, charge-neutral, large density fluctuations $\delta \rho/\rho \gg 1$, and corresponding random fluctuations of the dielectric permittivity $\epsilon$. Propagating in quasi-1D, waves in a medium with spatially random, time-varying, self-created fluctuations of dielectric permeability experience localization. Anderson self-localization of light leads to (i) reflection of EM waves by the under-dense pair plasma; (ii) a wave already present inside the plasma separates into bright trapped pockets and dark regions. Mild initial thermal spread restores wave propagation by suppressing the seeds of parametrically unstable density fluctuations. A circularly polarized driver produces linearly polarized structures, with position angle varying randomly between the bright pulses. We discuss possible applications to astrophysical Fast Radio Bursts.