Modulational and Filamentation Instabilities in Magnetized Cold-Fluid Plasmas

Waves in plasmas are subject to nonlinear processes that cause deformations to their envelope.



Modulational instabilities grow perturbations parallel to a wave's propagation direction and can give rise to localized structures, such as solitons and rogue (or freak) waves, which have been observed in laboratory and space plasmas. In certain laser-plasma interactions, significant pump depletion can be attributed to soliton generation in plasmas and has potential for practical applications such as particle acceleration.



Filamentation instabilities are responsible for the nonlinear break-up of a wave into filamentary structures transverse to its propagation direction. In inertial confinement fusion, laser beam filamentation is undesirable and significant effort has been devoted to mitigating this effect.



In this work, we derive governing equations for modulational and filamentation instabilities of a plane-wave eigenmode in magnetized homogeneous cold-fluid plasmas using a multiple scale expansion. Our results provide a general framework for computing the growth rates and thresholds of these instabilities, as well as for understanding how such instabilities may affect wave propagation in magnetized plasmas.