Formula_21209

\[\mathscr{Y}=\frac{1}{2}\left(\boldsymbol{E}^{2}-\boldsymbol{H}^{2}\right)+\frac{\alpha}{90 \pi F_{0}^{2}}\left[\left(\boldsymbol{E}^{2}-\boldsymbol{H}^{2}\right)^{2}+7(\boldsymbol{E} \boldsymbol{H})^{2}\right]+\ldots\]