行星和太阳内部的磁流体力学(英文)

Magnetohydrodynamics of Planetary and Solar Interiors

许多行星 (如木卫三 ,水星 ,地球 ,木星和土星 )和恒星 (如太阳 )具有内部磁场。对这些磁场的存在和变化的解释对行星科学家和天体物理学家是一个巨大的挑战。本文试图总结行星和恒星的导电流体内部磁流体力学研究的新近发展和困难。一般由热对流驱动的流动通过磁流体力学过程产生并维持在行星和恒星中的磁场。在行星中磁流体力学过程强烈地受到转动 ,磁场和球几何位型的综合影响。其动力学的关键方面涉及科里奥利力和洛伦兹力间的相互作用。在太阳中其流线 ,即处于对流层的薄的剪切流层在太阳的磁流体力学过程中扮演了一个基本的角色 ,并由之产生了 1 1年的太阳黑子周期。本文也给出了一个新的非线性三维太阳发电机模型。

Many planets (for example,Ganymede,Mercury,the Earth,Jupiter and Saturn) and stars (for example,the Sun) possess intrinsic magnetic fields.The explanation for their existence and variation remains a great challenge to planetary scientists and astrophysicists.This article attempts to review some recent developments and difficulties in the study of magnetohydrodynamics for the electrically conducting fluid interiors of planets and stars.It is the fluid motions,usually driven by thermal convection,that generate and sustain magnetic fields through magnetohydrodynamic processes in planets and stars.In planets,the magnetohydrodynamic processes are strongly affected by the combined and inseparable effects of rotation,magnetic fields and spherical geometry.The key dynamics involves the interaction between the Coriolis and Lorentz forces.In the Sun,it is the solar tachocline,a thin shear flow layer located at the base of the convection envelope,that plays an essential role in the solar magnetohydrodynamic processes which produce the 11-year sunspot cycle.Some results of a new nonlinear three-dimensional solar dynamo model are also presented.