Mansuripur Masud
College of Optical Sciences, The University of Arizona, Tucson, Arizona 85721, USA.
Opt Express. 2008 Sep 15;16(19):14821-35. doi: 10.1364/oe.16.014821.
Maxwell's macroscopic equations combined with a generalized form of the Lorentz law of force are a complete and consistent set of equations. Not only are these five equations fully compatible with special relativity, they also conform with conservation laws of energy, momentum, and angular momentum. We demonstrate consistency with the conservation laws by showing that, when a beam of light enters a magnetic dielectric, a fraction of the incident linear (or angular) momentum pours into the medium at a rate determined by the Abraham momentum density, E x H/c(2), and the group velocity V(g) of the electromagnetic field. The balance of the incident, reflected, and transmitted momenta is subsequently transferred to the medium as force (or torque) at the leading edge of the beam, which propagates through the medium with velocity V(g). Our analysis does not require "hidden" momenta to comply with the conservation laws, nor does it dissolve into ambiguities with regard to the nature of electromagnetic momentum in ponderable media. The linear and angular momenta of the electromagnetic field are clearly associated with the Abraham momentum, and the phase and group refractive indices (n(p) and n(g)) play distinct yet definitive roles in the expressions of force, torque, and momentum densities.
麦克斯韦宏观方程与洛伦兹力定律的广义形式相结合，构成了一套完整且自洽的方程组。这五个方程不仅与狭义相对论完全兼容，还符合能量、动量和角动量守恒定律。我们通过证明当一束光进入磁介质时，一部分入射线性（或角）动量以由亚伯拉罕动量密度(E×H/c²)和电磁场群速度(V(g))确定的速率流入介质，来证明与守恒定律的一致性。随后，入射、反射和透射动量的平衡作为力（或扭矩）传递到光束前沿的介质中，该光束以速度(V(g))在介质中传播。我们的分析不需要“隐藏”动量来符合守恒定律，也不会在可 ponderable 介质中电磁动量的性质方面陷入模糊不清的境地。电磁场的线性和角动量与亚伯拉罕动量明显相关，并且相折射率和群折射率（(n(p))和(n(g))）在力、扭矩和动量密度的表达式中起着截然不同但明确的作用。
