Uniform lifetime for classical solutions to the Hot, Magnetized, Relativistic Vlasov Maxwell system

Abstract

<p style='text-indent:20px;'>This article is devoted to the kinetic description in phase space of magnetically confined plasmas. It addresses the problem of stability near equilibria of the Relativistic Vlasov Maxwell system. We work under the Glassey-Strauss compactly supported momentum assumption on the density function <inline-formula><tex-math id="M1">\begin{document}$ f(t,\cdot) $\end{document}</tex-math></inline-formula>. Magnetically confined plasmas are characterized by the presence of a strong <i>external</i> magnetic field <inline-formula><tex-math id="M2">\begin{document}$ x \mapsto \epsilon^{-1} \mathbf{B}_e(x) $\end{document}</tex-math></inline-formula>, where <inline-formula><tex-math id="M3">\begin{document}$ \epsilon $\end{document}</tex-math></inline-formula> is a small parameter related to the inverse gyrofrequency of electrons. In comparison, the self consistent <i>internal</i> electromagnetic fields <inline-formula><tex-math id="M4">\begin{document}$ (E,B) $\end{document}</tex-math></inline-formula> are supposed to be small. In the non-magnetized setting, local <inline-formula><tex-math id="M5">\begin{document}$ C^1 $\end{document}</tex-math></inline-formula>-solutions do exist but do not exclude the possibility of blow up in finite time for large data. Consequently, in the strongly magnetized case, since <inline-formula><tex-math id="M6">\begin{document}$ \epsilon^{-1} $\end{document}</tex-math></inline-formula> is large, standard results predict that the lifetime <inline-formula><tex-math id="M7">\begin{document}$ T_\epsilon $\end{document}</tex-math></inline-formula> of solutions may shrink to zero when <inline-formula><tex-math id="M8">\begin{document}$ \epsilon $\end{document}</tex-math></inline-formula> goes to <inline-formula><tex-math id="M9">\begin{document}$ 0 $\end{document}</tex-math></inline-formula>. In this article, through field straightening, and a time averaging procedure we show a uniform lower bound (<inline-formula><tex-math id="M10">\begin{document}$ 0&lt;T&lt;T_\epsilon $\end{document}</tex-math></inline-formula>) on the lifetime of solutions and uniform Sup-Norm estimates. Furthermore, a bootstrap argument shows <inline-formula><tex-math id="M11">\begin{document}$ f $\end{document}</tex-math></inline-formula> remains at a distance <inline-formula><tex-math id="M12">\begin{document}$ \epsilon $\end{document}</tex-math></inline-formula> from the linearized system, while the internal fields can differ by order 1 for well prepared initial data.</p>