Analysis on energy density difference between linearly and circularly polarized electromagnetic waves

In this work, we shall demonstrate that both the time-rate of change of electromagnetic energy density and time-dependent Poynting vector of a circularly polarized electromagnetic wave (CPEMW) are significantly different from those of a linearly polarized electromagnetic wave (LPEMW), respectively. Subsequently, time-averaged stored energy density (TASED) of a CPEMW is also significantly different from that of a LPEMW. Our work may provide a new angle of view to deepen the understanding of characteristics of energy conversion and conservation of various electromagnetic waves, including linearity and nonlinearity, which my be helpful to provide possible way to experimentally test applicability of different expressions of TASED and related theories.