This paper introduces a new boundary element formulation for transient electromagnetic scattering by homogeneous dielectric objects based on the time-domain PMCHWT equation. To address dense-mesh breakdown, a multiplicative Calderon preconditioner utilizing a modified static electric field integral operator is employed. Large-timestep breakdown and late-time instability are simultaneously resolved by rescaling the Helmholtz components leveraging the quasi-Helmholtz projectors and using temporal differentiation and integration as rescaling operators. This rescaling also balances the loop and star components at large timesteps, improving solution accuracy. The resulting discrete system is solved using a marching-on-in-time scheme and iterative solvers. Numerical experiments for simply- and multiply-connected dielectric scatterers, including highly non-smooth geometries, corroborate the accuracy, stability, and efficiency of the proposed approach.

翻译：本文针对均匀介质物体的瞬态电磁散射问题，提出了一种基于时域PMCHWT方程的新型边界元公式。为应对密集网格失效问题，采用了一种利用修正的静态电场积分算子的乘法Calderon预条件子。通过利用准亥姆霍兹投影算子对亥姆霍兹分量进行重新标度，并使用时域微分和积分作为重标度算子，同时解决了大时间步长失效和后期不稳定性问题。这种重标度还在大时间步长下平衡了环量和星形分量，从而提高了求解精度。所得离散系统采用时间步进（marching-on-in-time）格式和迭代求解器进行求解。针对单连通和多连通介质散射体（包括高度非光滑几何结构）的数值实验，验证了所提方法的精确性、稳定性和高效性。