Unconditionally stable auxiliary differential equation Crank-Nicolson-approximate-decoupling FDTD algorithm for 2-D anisotropic magnetized plasma
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摘要: 针对二维各向异性磁等离子体提出一种有效的无条件稳定算法,新算法结合了辅助微分方程(ADE)方法与Crank-Nicolson approximate-decoupling(CNAD)时域有限差分算法仿真各向异性磁等离子体介质。传统的ADE-FDTD方法应用在一维各向异性色散介质具有较高的精度和效率,将提出的新算法ADE-CNAD-FDTD应用到二维各向异性磁等离子体介质中不仅解决了电磁波在具有各向异性和频率色散特性介质中传播的仿真难题,而且去除了CFL稳定性条件。该算法在保留了原有的精度情况下大幅度地提高了计算效率并成为无条件稳定的形式。给出一个算例证明该算法的有效性,通过模拟电磁波在磁等离子体中的传播,仿真结果与传统的ADE-FDTD算法对比,证实了该算法的高效率、无条件稳定性和高精度。
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关键词:
- 辅助微分方程 /
- Crank-Nicolson approximate-decoupling算法 /
- 时域有限差分 /
- 磁等离子体
Abstract: An effective unconditionally stable implementation of the auxiliary differential equation Crank-Nicolson-approximate-decoupling finite-difference time-domain (ADE-CNAD-FDTD) algorithm for 2-D anisotropic magnetized plasma is proposed. The conventional ADE-FDTD method for 1-D anisotropic dispersive media has high efficiency and accuracy. This paper extends this method to 2-D anisotropic magnetized plasma with the CNAD scheme. The proposed formulations not only solves the problem that incorporates both anisotropy and frequency dispersion at the same time, but also eliminates the Courant-Friedrich-Levy (CFL) stability constraint. A numerical example has been carried out to validate the proposed formulations in the 2-D FDTD domain composed of anisotropic magnetized plasma. The results prove that the proposed formulations significantly save time and perform stably with acceptable accuracy. -
表 1 传统ADE-FDTD和ADE-CNAD-FDTD两种算法占用的时间和内存
Table 1. Time and memory used by conventional ADE-FDTD method and ADE-CNAD-FDTD method
ADE-FDTD ADE-CNAD-FDTD CFLN=1 CFLN=2 CFLN=4 CFLN=6 time/s 78.880 167.650 80.870 40.850 27.340 memory/MB 82.604 90.844 90.872 90.760 90.876 -
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