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基于电流密度拉普拉斯变换方法改进的时域有限差分(LTJEC-FDTD)算法, 研究时变等离子体目标的电磁散射特性.由Maxwell方程和等离子体本构方程出发, 利用拉普拉斯变换和拉普拉斯逆变换, 推导出计算三维时变问题的时域有限差分(FDTD)算法的迭代式. 采用模式匹配方法验证了FDTD迭代式的正确性, 并通过计算等离子体球的雷达散射截面(RCS)验证了算法相关边界的正确性. 最后用LTJEC-FDTD算法分析了涂覆时变等离子体的战斧式巡航导弹的RCS.
关键词:
时变等离子体
雷达散射截面
模式匹配方法
时域有限差分方法 相似文献
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辛时域有限差分算法研究等离子体光子晶体透射系数 总被引:1,自引:0,他引:1
相较于传统的时域有限差分算法,辛时域有限差分算法具有高准确度性和低色散性.传统的时域有限差分算法的计算准确度较低,数值色散误差较大,并且破坏了麦克斯韦方程的辛结构,从而导致其稳定性较差.然而辛时域有限差分算法可以克服这些缺点,从而保证了整个仿真计算的准确性和稳定性.本文基于辛时域有限差分算法,对等离子体光子晶体的带隙特性,透射系数等进行了研究,并与传统的时域有限差分算法进行了对比,验证了辛时域有限差分算法的优势和可行性. 相似文献
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根据递推卷积原理,将磁化等离子体的频域介电系数过渡到时域,通过引入时域复数极化率张量和时域复数电位移矢量,得到了磁化等离子体的三维时域有限差分方法迭代式. 为了验证该方法,用它计算了非磁等离子体球的后向雷达散射截面,与移位算子法结果符合很好. 应用该方法计算和分析了磁化等离子体球的电磁波散射,发现其后向散射时域波形明显出现了交叉极化分量.
关键词:
递推卷积
磁化等离子体
电磁散射
时域有限差分方法 相似文献
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利用辛积分和高阶交错差分方法建立了求解含时薛定谔方程的高阶辛算法(SFDTD(4,4)).对空间部分的二阶导数采用四阶准确度的差分格式离散得到随时间演化的多维系统再引入四阶辛积分格式离散;探讨了SFDTD(4,4)法的稳定性,获得了含时薛定谔方程的一维以及多维的稳定性条件,并得到在含势能情况下该稳定性条件的具体表达式;借助复坐标沿伸概念,实现了SFDTD(4,4)法在量子器件模拟中的完全匹配层吸收边界条件.结合一维量子阱和金属场效应管传输的仿真,结果表明较传统的时域有限差分算法,SFDTD(4,4)有着更好的计算准确度,适用于长时间仿真.算法及相关结果可为实际量子器件的设计提供必要的参考. 相似文献
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提出了一种新的算法—高阶辛时域有限差分法(SFDTD(3,4):symplectic finite-difference time-domain)求解含时薛定谔方程.在时间上采用三阶辛积分格式离散,空间上采用四阶精度的同位差分格式离散,建立了求解含时薛定谔方程的高阶离散辛框架;探讨了高阶辛算法的稳定性及数值色散性.通过理论上的分析及数值算例表明:当空间采用高阶同位差分格式时,辛积分可提高算法的稳定度;SFDTD(3,4)法和FDTD(2,4)法较传统的FDTD(2,2)法数值色散性明显改善.对二维量子阱和谐振子的仿真结果表明:SFDTD(3,4)法较传统的FDTD(2,2)法及高阶FDTD(2,4)法有着更好的计算精度和收敛性,且SFDTD(3,4)法能够保持量子系统的能量守恒,适用于长时间仿真. 相似文献
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冷原子介质中的光孤子在电磁感应透明(EIT)的作用下表现出很多奇异的特性,对描述这些特性的理论模型的研究在光信号处理和传输方面具有重要的意义. 描述三能级冷原子EIT介质中空间孤立子演化的二维饱和非线性薛定谔方程被转化成辛结构的Hamilton系统, 利用辛几何算法离散Hamilton系统得到了相应离散的辛格式,并且利用辛格式数值模拟了三能级冷原子EIT介质中在相同振辐不同相位的两个、四个光孤子的相互作用行为. 数值实验结果表明: 冷原子介质中多个光孤子的相互作用行为不但与入射高斯光束的相位有关,还和入射高斯光束的方向有关. 入射的高斯光束能在冷原子介质中形成稳定的孤立子. 相似文献
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Fangfang Fu Linghua Kong & Lan Wang 《advances in applied mathematics and mechanics.》2009,1(5):699-710
In this paper, we establish a family of symplectic integrators for a class
of high order Schrödinger equations with trapped terms. First, we find its symplectic structure and reduce it to a finite dimensional Hamilton system via spatial discretization.
Then we apply the symplectic Euler method to the Hamiltonian system.
It is demonstrated that the scheme not only preserves symplectic geometry structure
of the original system, but also does not require to resolve coupled nonlinear
algebraic equations which is different from the general implicit symplectic schemes.
The linear stability of the symplectic Euler scheme and the errors of the numerical
solutions are investigated. It shows that the semi-explicit scheme is conditionally
stable, first order accurate in time and $2l^{th}$ order accuracy in space. Numerical tests
suggest that the symplectic integrators are more effective than non-symplectic ones,
such as backward Euler integrators. 相似文献
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In this paper, the Maxwell's equations are written as Hamilton canonical equations by using Hamilton functional variation method. Maxwell's equations can be discretized with symplectic propagation technique combined with high-order difference schemes approximations to construct symplectic finite difference time domain (SFDTD) method. The high-order dispersion equations of the scheme for space is deduced. The numerical dispersion analysis is included, and it is compared with the multiresolution time-domain (MRTD) method based on the Daubechies scaling functions. Numerical results show high efficiency and accuracy of the SFDTD method. 相似文献
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Roberto Beneduci James Brooke Ray Curran Franklin E. SchroeckJr. 《International Journal of Theoretical Physics》2011,50(12):3682-3696
We consider the Hamilton formulation as well as the Hamiltonian flows on a symplectic (phase) space. These symplectic spaces
are derivable from the Lie group of symmetries of the physical system considered. In Part 2 of this work, we then obtain the
Hamiltonian formalism in the Hilbert spaces of square integrable functions on the symplectic spaces so obtained. 相似文献
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This paper presents a two-step symplectic geometric approach to the reduction of Hamilton’s equation for open-chain, multi-body systems with multi-degree-of-freedom holonomic joints and constant momentum. First, symplectic reduction theorem is revisited for Hamiltonian systems on cotangent bundles. Then, we recall the notion of displacement subgroups, which is the class of multi-degree-of-freedom joints considered in this paper. We briefly study the kinematics of open-chain multi-body systems consisting of such joints. And, we show that the relative configuration manifold corresponding to the first joint is indeed a symmetry group for an open-chain multi-body system with multi-degree-of-freedom holonomic joints. Subsequently using symplectic reduction theorem at a non-zero momentum, we express Hamilton’s equation of such a system in the symplectic reduced manifold, which is identified by the cotangent bundle of a quotient manifold. The kinetic energy metric of multi-body systems is further studied, and some sufficient conditions are introduced, under which the kinetic energy metric is invariant under the action of a subgroup of the configuration manifold. As a result, the symplectic reduction procedure for open-chain, multi-body systems is extended to a two-step reduction process for the dynamical equations of such systems. Finally, we explicitly derive the reduced dynamical equations in the local coordinates for an example of a six-degree-of-freedom manipulator mounted on a spacecraft, to demonstrate the results of this paper. 相似文献
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Kozlov VV 《Chaos (Woodbury, N.Y.)》1996,6(1):1-5
The behavior of the phase trajectories of the Hamilton equations is commonly classified as regular and chaotic. Regularity is usually related to the condition for complete integrability, i.e., a Hamiltonian system with n degrees of freedom has n independent integrals in involution. If at the same time the simultaneous integral manifolds are compact, the solutions of the Hamilton equations are quasiperiodic. In particular, the entropy of the Hamiltonian phase flow of a completely integrable system is zero. It is found that there is a broader class of Hamiltonian systems that do not show signs of chaotic behavior. These are systems that allow n commuting "Lagrangian" vector fields, i.e., the symplectic 2-form on each pair of such fields is zero. They include, in particular, Hamiltonian systems with multivalued integrals. (c) 1996 American Institute of Physics. 相似文献
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建立了压电陶瓷材料电固耦合问题的Hamilton正则方程,并通过对全状态向量分离变量,给出了压电陶瓷材料的共轭辛正交解析解。 相似文献