Electro-magnetic Field Equations

The linear law relating electric stress components to components of elastic strain, electric, and thermal displacements is now

$${\bf \sigma_2}~=~ \displaystyle \mathop{\mbox{${\bf c_{21}}$... ..._{\mbox{$\sim$}} {{\partial}\over{\partial t}}~{\bf \epsilon_3}$$ (22)

Consequently we end up with the following coupled electromagnetic field equations in terms of elastic strains:  

$$- \displaystyle \mathop{\mbox{${\bf curl}$}}_{\mbox{$\sim$}}... ...}}_{\mbox{$\sim$}} ~{\partial \over{\partial t}} {\bf \sigma_2}$$ (23)