有关系统能量耗散运动的功率谱分析

研究有限哈密顿系统能量耗散过程的动力学问题，通过合理的数值模拟，实现有关系统的能量耗散过程，直接从哈密顿量的变化情况出发，难以分析不同自由度在能量耗散过程的动力学行为，我们采用功率谱方法研究有关系统运动中的坐标q（t）或动量p（t）的演化过程，结果发现在有关系统的能量耗散过程中，有关自由度运动的频率成分向高频和低频方向都有明显展宽，随着无关系统自由度增多，展宽明显增加；低频成分比较稳定，高频成分随着时间的发展逐渐减少，

Spectrum Analysis on Dissipative Motion in Relevant System

In order to study the dynamical problems about energy dissipation in a finite Hamiltonian system, a dissipative motion in relevant system need to be realized by a reliable numerical simulation. From the numerical results of Hamilton- ians, energy transport phenomenonbetween relevantand irrelevantsubsystems can be discussed butit is difficult to analyze the dynamical behaviors in the dissipative process for different degree of freedom (DOF). By employing power spectrum analysis on coordinate or moment of the motion in relevant system, it is found that during the dissipative process, distribution of the spectral density about the motion in relevant system extends to either lower or higher frequency. The more irrelevant degrees of freedom are, the broader the distribution extends. Higher frequencies decrease as time evolves but there are no obvious changes for lower components.