Maxwell stress tensor
= Maxwell stress tensor
{c}
{wiki}
With electromagnetic momentum density $\mathbf g=\epsilon_0\mathbf E\times\mathbf B$, the momentum-flux convention
$$
\sigma_{ij}=-\epsilon_0E_iE_j+\frac{\epsilon_0}{2}E^2\delta_{ij}
-\frac1{\mu_0}B_iB_j+\frac1{2\mu_0}B^2\delta_{ij}
$$
satisfies
$$
\partial_tg_j+\partial_i\sigma_{ij}=-(\rho\mathbf E+\mathbf J\times\mathbf B)_j.
$$