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Asymptotic stability of Couette flow in a strong uniform magnetic field for the Euler-MHD system

Analysis of PDEs 2023-05-09 v1

Abstract

In this paper, we prove the asymptotic stability of Couette flow in a strong uniform magnetic field for the Euler-MHD system, when the perturbations are in Gevrey-1s\frac{1}{s}, (12<s1)(\frac12<s\leq 1) and of size smaller than the resistivity coefficient μ\mu. More precisely, we prove (1) the μ13\mu^{-\frac13}-amplification of the perturbed vorticity, namely, the size of the vorticity grows from ωinGλ0μ\|\omega_{\mathrm{in}}\|_{\mathcal{G}^{\lambda_{0}}}\lesssim \mu to ωGλμ23\|\omega_{\infty}\|_{\mathcal{G}^{\lambda'}}\lesssim \mu^{\frac23}; (2) the polynomial decay of the perturbed current density, namely, jL2c0t2min{μ13,t}\left\|j_{\neq}\right\|_{L^2}\lesssim \frac{c_0 }{\langle t\rangle^2 }\min\left\{\mu^{-\frac13},\langle t \rangle\right\}; (3) and the damping for the perturbed velocity and magnetic field, namely, (u1,b1)L2c0μtmin{μ13,t},(u2,b2)L2c0μt2min{μ13,t}. \left\|(u^1_{\neq},b^1_{\neq})\right\|_{L^2}\lesssim \frac{c_0\mu }{\langle t\rangle }\min\left\{\mu^{-\frac13},\langle t \rangle\right\}, \quad \left\|(u^2,b^2)\right\|_{L^2}\lesssim \frac{c_0\mu }{\langle t\rangle^2 }\min\left\{\mu^{-\frac13},\langle t \rangle\right\}. We also confirm that the strong uniform magnetic field stabilizes the Euler-MHD system near Couette flow.

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Cite

@article{arxiv.2305.04052,
  title  = {Asymptotic stability of Couette flow in a strong uniform magnetic field for the Euler-MHD system},
  author = {Weiren Zhao and Ruizhao Zi},
  journal= {arXiv preprint arXiv:2305.04052},
  year   = {2023}
}

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74 pages