Approximation of a quasilinear Schrödinger equation by a Klein–Gordon equation in space dimension 2

Article type: Research Article

Authors: Colin, Mathieu

Affiliations: Université Paris‐Sud, UMR de Mathématiques, Bat. 425, 91405 Orsay cedex, France E‐mail: Mathieu.Colin@math.u‐psud.fr

Abstract: In this article, we study the nonlinear plasma wave equation \[-\varepsilon^{2}\dfrac{\curpartial^{2}u_{\varepsilon}}{\curpartial t^{2}}+2\mathrm{i}\dfrac{\curpartial u_{\varepsilon}}{\curpartial t}+\Delta u_{\varepsilon}=\big(\dfrac{1}{\sqrt{1+|u_{\varepsilon}|^{2}}}-1\big)u_{\varepsilon}+\dfrac{\Delta(\sqrt{1+|u_{\varepsilon}|^{2}})}{\sqrt{1+|u_{\varepsilon}|^{2}}}u_{\varepsilon}\] with initial data $u_{\varepsilon}(\cdot,0)=u_{0}^{\varepsilon}(\cdot)\in H^{8}(\mathbb{R}^{2}),\ \curpartial_{t}u_{\varepsilon}(\cdot,0)=u_{1}^{\varepsilon}(\cdot)\in H^{7}(\mathbb{R}^{2})$. We show that the Cauchy problem is locally well‐posed on an interval [0,T] where the time T is independent of ε if u1ε is small enough. Then, we demonstrate the strong convergence of uε towards the solution u of a nonlinear relativistic Schrödinger equation as ε goes to 0.

Journal: Asymptotic Analysis, vol. 34, no. 3-4, pp. 275-309, 2003