线性介质中伴随电磁场存在而附加的自由能密度

The Additional Density of Free Energy in Linear Medium Due to Existence of Electromagneitic Field

本文证明了在线性介质中,通常所说的电磁场能量密度的表示式w=1/2((?)·(?)+(?)·(?))。实质上是所考虑系统的自由能密度的增量。

In this paper, it is proved that (in linear medium) the expression of electromagneitic energy density w=1/2((?)·(?)+(?)·(?)), as it usually to be said, substantially is increment of free energy density of considered system.