30 \(H_{e}(x,t)=\left\{\begin{matrix}\max\ {\psi_{e}}^{+}\left(\mathbf{\varepsilon}^{e}(x,\mathbf{\tau})\right)\text{\ \ \ }\text{if}\ \varphi\geq\varphi_{c}\\ {\psi_{e}}^{+}\left(\mathbf{\varepsilon}^{e}(x,\mathbf{\tau})\right)\text{\ \ \ \ \ \ \ \ \ \ \ \ }\text{otherwise}\\ \end{matrix}\right.\ \)