In the Vlasov-Poisson equation, every configuration which is homogeneous in space provides a stationary solution. Penrose gave in 1960 a criterion for such a configuration to be linearly unstable. While this criterion makes sense in a measure-valued setting, the existing results concerning nonlinear instability always suppose some regularity with respect to the velocity variable. Here, thanks to a multiphasic reformulation of the problem, we can prove an “almost Lyapounov instability” result for the Vlasov-Poisson equation, and an ill-posedness result for the kinetic Euler equation and the Vlasov-Benney equation (two quasineutral limits of the Vlasov-Poisson equation), both around any unstable measure.
Cite this article
Aymeric Baradat, Nonlinear instability in Vlasov type equations around rough velocity profiles. Ann. Inst. H. Poincaré Anal. Non Linéaire 37 (2020), no. 3, pp. 489–547DOI 10.1016/J.ANIHPC.2019.12.002