## Prof. Xing Wei (魏星)Department of Astronomy email: xingwei@bnu.edu.cn |

I plan to recruit graduate students for these projects.

Internal structure of exoplanets (in collaboration with FAST program).

Tidal waves and tidal turbulence in planets and stars.

Reflected and transmitted waves at the interface of radiative and convective regions.

Magnetic effect on stellar oscillations.

Instability in disk caused by differential rotation, magnetic field and self-gravity.

Students with the background of mathematics, physics, fluid mechanics, astronomy or geophysics are welcome to contact me. The projects are not limited to the above ones and you are encouraged to propose your own ideas.

My research interests are theoretical astrophysics, especially astrophysical fluid dynamics and plasma physics. For example, how planetary or stellar magnetic fields are generated and evolve, how tidal waves in binary system propagate and dissipate, and why proto-planetary or black hole disk becomes unstable, etc. To understand these problems, mathematical models need to be built and studied by means of order-of-magnitude estimation and paper-and-pencil calculation with a little numerical work but not massive parallel computation. Below are some objects that I study. From left to right: Earth's magnetic fields, Jupiter's red spot, stellar interior, tides in binary stars, and disk accretion.

B.S. Tsinghua University (mechanics), Sep 1998 - Jul 2002

M.S. Tsinghua University (mechanics), Sep 2002 - Jul 2004

Ph.D. University of Cambridge (fluid mechanics), Oct 2004 - Dec 2008

postdoc, ETH Zurich (geophysics), Jan 2009 - Mar 2011

research associate, University of Göttingen (geophysics), Apr 2011 - Jun 2013

research scholar, Princeton University (astrophysics), Jul 2013 - Aug 2015

associate professor, Shanghai Jiao Tong University (applied mathematics), Sep 2015 - Mar 2019

professor, Beijing Normal University (astronomy), Apr 2019 - present

Wei, X. and Lin, D. N. C. (2020): Magnetic fields of young planets. in preparation.

Wei, X. (2020): On the evolution of global ocean tides.

*Geophysical and astrophysical fluid dynamics*, under review.Wei, X. (2020): Wave reflection and transmission at the interface of convective and stably stratified regions in a rotating star or planet.

*Astrophysical Journal*, 890: 20Wei, X. (2019): Surface tide on a rapidly rotating body.

*Monthly Notices of the Royal Astronomical Society*, 484: 3017-3021.Wei, X. (2018): Dynamo induced by time-periodic force.

*Astrophysical Journal Letters*, 855: L7.Wei, X. (2018): The magnetic effect on dynamical tide in rapidly rotating astronomical objects.

*Astrophysical Journal*, 854: 34.Wei, X. (2016): Calculating rotating hydrodynamic and magnetohydrodynamics waves to understand magnetic effects on dynamical tides.

*Astrophysical Journal*, 828: 30.Wei, X. (2016): The combined effect of precession and convection on dynamo action.

*Astrophysical Journal*, 827: 123.Wei, X. (2016): Linear and nonlinear responses to harmonic force in rotating flow.

*Journal of Fluid Mechanics*, 796: 306-317.Wei, X. (2016): Decay of isotropic flow and anisotropic flow with rotation or magnetic field or both in a weakly nonlinear regime.

*Acta Mechanica*, 227: 2403-2413.Wei, X., Ji, H. and Goodman, J., et. al. (2016): Numerical simulations of the Princeton magneto-rotational instability experiment with conducting axial boundaries.

*Physical Review E*, 94: 063107.Wei, X. and Goodman, J. (2015): On obliquely magnetized and differentially rotating stars.

*Astrophysical Journal*, 806: 50.Wei, X. (2014): Kinematic dynamo induced by helical waves.

*Geophysical and Astrophysical Fluid Dynamics*, 109: 159-167.Wei, X., Arlt, R. and Tilgner, A. (2014): A simplified model of collision-driven dynamo action in small bodies.

*Physics of the Earth and Planetary Interiors*, 231: 30-38.Wei, X. (2013): Local analysis of the magnetic instability in rotating magneto-hydrodynamics with the short-wavelength approximation.

*Geophysical and Astrophysical Fluid Dynamics*, 108: 213-221.Wei, X. and Tilgner, A. (2013): Stratified precessional flow in spherical geometry.

*Journal of Fluid Mechanics*, 718: R2.Hollerbach, R., Wei, X., Noir, J. and Jackson, A. (2012): Electromagnetically driven flows in a rapidly rotating spherical shell.

*Journal of Fluid Mechanics*, 725: 428-445.Wei, X., Jackson, A. and Hollerbach, R. (2012): Kinematic dynamo action in spherical Couette flow.

*Geophysical and Astrophysical Fluid Dynamics*, 106: 681-700.Wei, X. and Hollerbach, R. (2010): Magnetic spherical Couette flow in linear combinations of axial and dipolar fields.

*Acta Mechanica*, 215: 1-8.Wei, X. and Hollerbach, R. (2008): Instabilities of Shercliff and Stewartson layers in spherical Couette flow.

*Physical Review E*, 78: 026309.Wei, X., Zhang, J. and Zhou, LX. (2004): A new algebraic mass flux model for simulating turbulent mixing in swirling flow.

*Numerical Heat Transfer B*, 45: 283-300.

Mathematical Methods, undergraduate supervision, Cambridge, full 2006

Plasma Physics, graduate seminar, Shanghai, spring 2016

Calculus, undergraduate lecture, Shanghai, fall 2017

Fluid Mechanics, graduate lecture, Shanghai, fall 2017, fall 2018

Numerical Analysis, graduate lecture, Shanghai, fall 2018

Classical Mechanics, undergraduate lecture, Beijing, spring 2020

This course is an introduction to fluid mechanics. The contents involve physical property of fluid, Euler equation and Navier-Stokes equation, vortex dynamics, waves in fluid, boundary layer theory, flow instability, introduction to turbulence, introduction to shocks, and introduction to geophysical and astrophysical fluid dynamics.

这门课程介绍流体力学的基本知识。课程内容包括：流体的基本性质，流体力学基本方程，流体中的涡，流体中的波，边界层理论，流动稳定性，湍流简介，激波简介，地球物理和天体物理流体力学简介。

Syllabus (教学内容)

掌握控制体的方法推导流体力学方程的积分形式和微分形式。

掌握可压缩和不可压缩流动的特性。

掌握流体中常见的几种涡，能够从涡量解释阻力和升力。

掌握流体中常见的几种波，掌握推导色散关系和群速度的方法。

掌握边界层的概念和推导，掌握量级分析的方法。

掌握流动稳定性分析的方法，能够根据不同的流动给出稳定性的特征值问题。

了解湍流的多尺度和标度率的量纲分析的方法。

了解激波出现的原因，能够写出一维激波的间断条件。

了解旋转流体、分层流体、磁流体的基本方程，知道它们在大气、海洋、天文上的应用。

Reference books (参考书)

Elementary fluid dynamics, Acheson, Oxford University Press, 1990

Fluid mechanics, Landau & Lifshitz, Clarendon Press, 1959

Waves in fluids, Lighthill, Cambridge University Press, 1978

Hydrodynamic and hydromagnetic stability, Chandrasekhar, Dover Press, 1981

Astrophysical flows, Pringle & King, Cambridge University Press, 2007

Syllabus and textbook (教学内容和教科书)

http://math.sjtu.edu.cn/course/Ngraduate/category.asp?name=9001&secondName=9327

Dorothy Hodgkin Postgraduate Awards, University of Cambridge, 2004

1000 Youth Talent Plan, Chinese government, 2016

1000 Youth Talent Grant, National Natural Science Foundation of China, 2016

General Program, National Natural Science Foundation of China, 2019

General Program, National Natural Science Foundation of Beijing, 2020

Magnetic Reconnection, Shanghai, Jan 2017

Physics of Planetary and Stellar Interiors, Nanjing, Apr 2017