2025/09/24 by Maxim Lyutikov, Victor Gurarie, Lyutikov, Maxim +1 · 1 citation
#physics.plasm-ph #astro-ph.HE #cond-mat.dis-nn
paper · pdf · doi:10.48550/arxiv.2509.20594
We demonstrate that in pair plasma weakly nonlinear electromagnetic waves, a0 ≤ 1, experience Anderson self-localization. The beat between the driver and a back-scattered wave creates charge-neutral, large random, yet correlated density fluctuations δn/n0 ≫ 1, and corresponding fluctuations of the dielectric permittivity ε (random plasma density grating). Propagating in quasi-1D, waves in a medium with spatially random self-created fluctuations of dielectric permeability experience localization. In the linear regime, the instability can be classified as Induced Brillouin Scattering; it is described by the parameter ρL = ( a0 ωp/ ω)2/3 ≪ 1 , related to the Pierce parameter of Free Electron Lasers. In the cold case, the growth rate is Γ≈ ρL ω≪ 1 (a0 is laser nonlinearity parameter, ωp is plasma frequency, ω is the laser frequency). 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 with Θ≡ kB T/(me c2) ≈ a02, 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. Time-variability of the resulting density structures does not suppress localization due to remaining correlations (not white noise). We discuss possible applications to astrophysical Fast Radio Bursts.