arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.15094math.AP
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拟齐次理想MHD系统的严格推导及其适定性

Rigorous derivation and well-posedness of a quasi-homogeneous ideal MHD system

Dimitri Cobb, Francesco Fanelli

摘要:

本文的目的是双重的。一方面,我们引入了一个经典理想MHD系统的拟齐次形式,并研究了它在临界Besov空间$B^s_{p,r}(\mathbb{R}^d)$,$d\geq2$,$1<p<+\infty$和Lipschitz条件下的适定性,以及在临界Besov空间$s>1+d/p$和$r\in[1,+\infty]$,或$s=1+d/p$和$r=1$中的适定性.一个关键因素是系统\textsl{via}的重新表述,即所谓的Elsässer变量。另一方面,我们给出了一个严格的理由准均匀MHD模型,无论是在理想的情况下,在耗散的情况下:当$d=2$,我们将从一个非均匀的不可压缩MHD系统与科里奥利力,在低Rossby数的制度和周围的恒定状态的小密度变化。我们的证明方法依赖于原始系统的相对熵不等式,并产生精确的收敛速度,这取决于初始数据的大小,Rossby数的顺序和粘度和电阻率系数的规律性。

英文摘要:

The goal of this paper is twofold. On the one hand, we introduce a quasi-homogeneous version of the classical ideal MHD system and study its well-posedness in critical Besov spaces $B^s_{p,r}(\mathbb{R}^d)$, $d\geq2$, with $1<p<+\infty$ and under the Lipschitz condition $s>1+d/p$ and $r\in[1,+\infty]$, or $s=1+d/p$ and $r=1$. A key ingredient is the reformulation of the system \textsl{via} the so-called Elsässer variables. On the other hand, we give a rigorous justification of quasi-homogeneous MHD models, both in the ideal and in the dissipative cases: when $d=2$, we will derive them from a non-homogeneous incompressible MHD system with Coriolis force, in the regime of low Rossby number and for small density variations around a constant state. Our method of proof relies on a relative entropy inequality for the primitive system, and yields precise rates of convergence, depending on the size of the initial data, on the order of the Rossby number and on the regularity of the viscosity and resistivity coefficients.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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