Linear damping of inhomogenous Alfvén wave
主 题: Linear damping of inhomogenous Alfvén wave
报告人: 任偲骐博士，研究方向是流体相关的偏微分方程 (304am永利集团)
时 间: 2016-12-02 12：00-13：15
地 点: 理科一号楼1560
In 1942, physicist Hannes. Alfvén predicted a type of magneto-hydrodynamic wave in plasma due to the perturbation around a homogenous magnetic field. Alfven found out that the wave velocity in the sun was consistent with the speed of the moving sunspot. This wave, named as Alfvén wave, was observed in many magnetized plasmas and now widely recognized of considerable importance. Unlike homogeneous situation, if the perturbation is around non-uniform magnetic field, the wave turns out to decay in large time. Physicists have formally derived the decay rate of fluid velocity, O (1 / t). In this talk, I will give a rigorous proof of this decay rate and the longtime behavior of the other quantities in this system. I will also explain the connection between our mathematical mechanism and the physicist’s one called “phase mixing”. 1942年, 物理学家H. Alfvén从磁流体动力学（magneto-hydrodynamics）角度，预言在等离子体中存在一种波：在均匀磁场附近扰动下产生。Alfvén 计算了太阳中这种波的波速，发现和太阳黑子的移动速度大致吻合。这种波被命名为阿尔文(Alfvén) 波，后来在很多等离子体中被观测到，因此得到广泛研究。不同于均匀情形，如果对非均匀磁场扰动，产生的阿尔文波会衰减（Damping）。物理学家形式的推导了磁流体扰动速度关于时间的衰减率是O(1\t)。 本次报告中，我将介绍我们是如何从数学上严格得到这个衰减率，阐释我们证明中的数学机制和物理学家的“相混（phase mixing）”机制之联系，并且精确描述其他扰动量的长时间性态。 报名方式：请有意参加的老师在2016年12月1日（周四）晚10点前发送邮件至smsxueshu@126.com,我们将回复邮件和您确认,邮件报名方式仅限于老师，有意参加的同学请点击报名链接https://www.sojump.hk/jq/10939565.aspx ，谢谢！
