Electromagneto-quasistatic (EMQS) field formulations are often dubbed as Darwin-type field formulations which approximate the Maxwell equations by neglecting radiation effects while modelling resistive, capacitive, and inductive effects. A common feature of EMQS field models is the Darwin-Amp\'ere equation formulated with the magnetic vector potential and the electric scalar potential. EMQS field formulations yield different approximations to the Maxwell equations by choice of additional gauge equations. These EMQS formulations are analyzed within the port-Hamiltonian system (PHS) framework. It is shown via the PHS compatibility equation that formulations based on the combination of the Darwin-Amp\'ere equation and the full Maxwell continuity equation yield port-Hamiltonian systems implying numerical stability and specific EMQS energy conservation.

翻译：电磁准静态（EMQS）场表述常被称为达芬型场表述，通过忽略辐射效应同时建模电阻、电容和电感效应来近似麦克斯韦方程组。EMQS场模型的一个常见特征是用磁矢量势和电标量势表述的达芬-安培方程。通过选择不同的附加规范方程，EMQS场表述对麦克斯韦方程组产生了不同的近似。这些EMQS表述在端口哈密顿系统（PHS）框架内进行了分析。通过PHS兼容性方程证明，基于达芬-安培方程与完整麦克斯韦连续性方程组合的表述构成了端口哈密顿系统，从而隐含数值稳定性与特定的EMQS能量守恒特性。