摘要
运动介质系统中的电磁场随时间的演化规律是工程技术和应用物理都很关注的核心问题之一.本文首先对比和分析了基于狭义相对论的标准理论和伽利略电磁学的相关发展.接着我们从四大物理定律出发,通过麦克斯韦方程组的积分式,推导出适用于非匀速运动介质在非相对论近似下的动生麦克斯韦方程组.该方程组引入了(机械)力-电-磁的耦合场,拟解决在非惯性系中低速变速运动介质以及介质形状和边界随时间变化情况下的电磁场动力学变化规律.方程组中引入的动生极化项P_(S)是由外力作用到带电介质并引起介质的加速运动而导致的,它不同于由电场导致的感应极化项P.当存在力-电-磁多场耦合时,方程组不应该保持洛伦兹协变性,且系统的电磁能量不守恒,但封闭系统的总能量守恒.介质运动是产生电磁波的源之一(动生电),描述介质里面的电磁现象使用动生麦克斯韦方程组;当源产生的电磁波在空间传播时使用狭义相对论和经典的麦克斯韦方程组,两者在介质界面相接并满足边界条件.
The governing rules of the electromagnetic fields for a moving media system are important for engineering applications and physics.A systematic comparison of special relativity and Galilean electromagnetism is first given.Then,starting from the integral form of the four physics laws,the Maxwell’s equations for a mechano-driven slow-moving media system are derived.Through the coupled mechanical force-electric-magnetic fields,the expanded Maxwell’s equations should reveal the dynamics of an electromagnetic field for a general case,in which the medium has a time-dependent volume,shape,and boundary and may move in an arbitrary,slowmoving velocity field v(r,t)in a noninertial system.A mechano-induced polarization term P_(S)is introduced in the displacement vector to represent the polarization produced by the relative movement of the charged media under an external force.Notably,the additional term P_(S)is different from the medium polarization P because of the external electric field E;thus,these terms cannot be merged even in mathematical form.Most importantly,the expanded equations may not satisfy Lorentz covariance because the energy of electricity and magnetism is not conservative under external mechanical energy,but the total energy of the closed system is conservative.At last,the charged moving media are confirmed to be sources of generating electromagnetic radiation(a motion-generated electromagnetic field).The generated electromagnetic wave within the medium can be described using the expanded Maxwell’s equations.Its propagation in space can be thoroughly characterized using the standard Maxwell’s equations and special relativity,which meet at the medium interface governed by the boundary conditions.
作者
王中林
邵佳佳
WANG ZhongLin;SHAO JiaJia(Beijing Institute of Nanoenergy and Nanosystems,Chinese Academy of Sciences,Beijing 101400,China;School of Nanoscience and Technology,University of Chinese Academy of Sciences,Beijing 100049,China;School of Materials Science and Engineering,Georgia Institute of Technology,Atlanta 30332-0245,USA)
出处
《中国科学：技术科学》
EI
CSCD
北大核心
2022年第8期1198-1211,共14页
Scientia Sinica(Technologica)
关键词
动生麦克斯韦方程组
动生极化
相对论
Maxwell’s equations for mechano-driven slow-moving media
mechano-induced polarization
special relativity
