Force and Hidden Momentum for Classical Microscopic Dipoles
Force and Hidden Momentum for Classical Microscopic Dipoles
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经典微观偶极子的力和隐藏动量
DOI：
10.2528/pierb18092007
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
A. Yaghjian
中科院分区：
文献类型：
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作者：
A. Yaghjian
本文回顾了隐动量的概念，并从麦克斯韦方程组出发，首次严格推导了在有限带宽但任意时变场中作用在任意形状电小理想导体上的电磁力。证明了这些理想导体的安培磁偶极子存在一个“隐动量”电磁力，使得作用在这些时变安培磁偶极子上的力等于作用在具有相同时变磁偶极矩的磁荷磁偶极子上的力。在平面波照射下的完美导电球的精确Mie解被用来证明任意形状的电小完美导体上的总的和隐藏的动量力的表达式正确地预测完美导电球上的力。值得注意的是，它被发现，在球体的表面处的四极场是必需的，以获得正确的球上的总力，即使四极矩是可以忽略不计的相比，作为电尺寸的球体接近零的偶极矩。
The concept of hidden momentum is reviewed and the first rigorous derivation from Maxwell's equations is provided for the electromagnetic force on electrically small perfect electric conductors of arbitrary shape in bandlimited but otherwise arbitrarily time-varying fields. It is proven for the Amperian magnetic dipoles of these perfect conductors that a "hidden-momentum" electromagnetic force exists that makes the force on these time varying Amperian magnetic dipoles equal to the force on magnetic-charge magnetic dipoles with the same time varying magnetic dipole moment in the same time varying externally applied fields. The exact Mie solution to the perfectly conducting sphere under plane-wave illumination is used to prove that the expressions for the total and hidden-momentum forces on the arbitrarily shaped electrically small perfect conductors correctly predict the forces on perfectly conducting spheres. Remarkably, it is found that the quadrupolar fields at the surface of the sphere are required to obtain the correct total force on the sphere even though the quadrupolar moments are negligible compared to the dipole moments as the electrical size of the sphere approaches zero.