Electromagnetic Wave Propagation in Axisymmetric Time-Varying Plasma Using Newton-ADE BOR-FDTD

This letter presents the body-of-revolution finite-difference time-domain (BOR-FDTD) method based on Newton equation and incorporating the auxiliary differential equation (ADE) technique for simulating electromagnetic wave propagation in axisymmetric time-varying plasmas. The classical BOR-FDTD method reduces computational costs by exploiting axisymmetric geometries but is limited to stationary plasmas. Conventional time-varying plasma models oversimplify electron dynamics by phenomenologically linking time-varying electron density to the current density, thereby neglecting electrons microscopic dynamics. To address these limitations, we propose the Newton-ADE BOR-FDTD method, a first-principles framework derived from Newton's equations of motion. This approach captures more detailed dynamic information, especially when the time derivative of the logarithm of the electron density exceeds the collision frequency.  It maintains computational efficiency while preserving microscopic electron kinetics. Finally, numerical examples validate both the superior accuracy and effectiveness of the proposed framework.