Yuri Cher | Searcharxiv

arXiv2019

Blowing Up Solutions to the Zakharov System for Langmuir Waves

Langmuir waves take place in a quasi-neutral plasma and are modeled by the Zakharov system. The phenomenon of collapse, described by blowing up solutions plays a central role in their dynamics. We present in this article a review of the main mathematical properties of blowing up solutions. They include conditions for blowup in finite or infinite time, description of self-similar singular solutions and lower bounds for the rate of blowup of certain norms associated to the solutions.

math.AP↗

arXiv2016

Local structure of singular profiles for a Derivative Nonlinear Schrödinger Equation

The Derivative Nonlinear Schrödinger equation is an $L^2$-critical nonlinear dispersive equation model for Alfvén waves in space plasmas. Recent numerical studies on an $L^2$-supercritical extension of this equation provide evidence of finite time singularities. Near the singular point, the solution is described by a universal profile that solves a nonlinear elliptic eigenvalue problem depending only on the strength of the nonlinearity. In the present work, we describe the deformation of the profile and its parameters near criticality, combining asymptotic analysis and numerical simulations.

math.AP↗