LAUSR

Abstract There exist several unequivalent expressions of stored and dissipated energy densities. It is still lack of correctness judgement for these expressions. Here, we shall propose that the time-averaged form of Poynting’s theorem, which implies that the net power flowing into a closed surface equals the power dissipated in the enclosed volume, may be taken as a correctness criterion for expression of dissipated energy density. Then we review the common expressions of stored and dissipated energy densities and provide possibility to derive equivalent expressions by using different ways. This work may be helpful to gain a better understanding of storage and dissipation of energy in the electromagnetic wave.