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【青年学者论坛】Stability and instability of Kelvin-Stuart cat's eyes flows

发布人:发布时间: 2023-09-06

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题目:Stability and instability of Kelvin-Stuart cat's eyes flows

报告人:朱昊 Hao Zhu,Nanjing University

时间:北京时间2023年9月13日(周三)上午 10:10-12:00

地点:鼓楼校区蒙民伟楼1105会议室

腾讯会议:879-863-651 

密码:981868 

摘要Kelvin-Stuart vortices are classical mixing layer flows with many applications in fluid mechanics, plasma physics and astrophysics. We prove that the whole family of Kelvin-Stuart vortices is nonlinearly stable for co-periodic perturbations, and linearly unstable for multi-periodic or modulational perturbations. This verifies a conjecture since the discovery of the Kelvin-Stuart cat's eyes flows in the 1960s. Kelvin-Stuart cat's eyes also appear as magnetic islands which are magnetostatic equilibria for the 2D ideal MHD equations in plasmas. We prove nonlinear stability of Kelvin-Stuart magnetic islands for co-periodic perturbations, and give a rigorous proof of the coalescence instability, which is important for magnetic reconnection. This talk is based on a joint work with Shasha Liao and Zhiwu Lin.