Stability estimates for magnetized Vlasov equations
Alexandre Rege
TL;DR
This work studies stability of magnetized Vlasov–Poisson and Vlasov equations using optimal transport tools. It extends Loeper's $2$-Wasserstein stability and Iacobelli's nonlinear control to the magnetized VP system with non-uniform magnetic field, revealing anisotropy that requires stronger velocity decay in one datum, and it derives two explicit stability statements under suitable smallness assumptions. It also provides an improved Dobrushin-type $W_1$-estimate for the magnetized Vlasov equation with a uniform magnetic field, with explicit dimension-dependent bounds that recover the unmagnetized limits as the magnetic field vanishes. Together, these results illuminate how external magnetic fields influence stability in kinetic models and offer quantitative, transport-based stability criteria applicable to quasi-neutral and related regimes.
Abstract
We present two results related to magnetized Vlasov equations. Our first contribution concerns the stability of solutions to the magnetized Vlasov-Poisson system with a non-uniform magnetic field using the optimal transport approach introduced by Loeper [24]. We show that the extra magnetized terms can be suitably controlled by imposing stronger decay in velocity on one of the distribution functions, illustrating how the external magnetic field creates anisotropy in the evolution. This allows us to generalize the classical 2-Wasserstein stability estimate by Loeper [24, Theorem 1.2] and the recent stability estimate using a kinetic Wasserstein distance by Iacobelli [20, Theorem 3.1] to the magnetized Vlasov-Poisson system. In our second result, we extend the improved Dobrushin estimate by Iacobelli [20, Theorem 2.1] to the magnetized Vlasov equation with a uniform magnetic field.
