太阳风速度的周期结构分析

本文应用功率谱估计中的加窗法和最大熵法对第20太阳活动周太阳风速度的周期结构进行了频谱分析;为了克服太阳活动高年瞬变扰动的干扰,本文还用互相关滤波方法与谱分析进行了比较。得到如下结果:除了个别年代外,在太阳活动周的所有相位里,太阳风速度几乎都存在13天和27天两种主要周期变化成份。在一些年里,还有9天的周期成份存在。 

The Analysis of Periodic Structure of Solar Wind Velocity

Three kinds of spectrum analysis method are performed in order to study the regularities of distribution of solar wind. The first one is the general log power spectrum from which it can be seen that there is a overweighted 13-day period during the descending and minimum phases of the sunspot cycle, but in the ascending and maximum phases of the sunspot cycle, the spectrum is random. It seems that solar wind is in disorder during these periods. The second kind of spectrum analysis used is the maximum entropy spectrum which has better spectrum resolution. This gives out a different situation that the solar wind in the years of ascending and maximum phases of this sunspot cycle also possesses the 13-day period which far overweight the other periods. In order to verify further that there is really the same regularity of distribution of solar wind in ascending and maximum phases of the sunspot cycle as that in descending and minimum phases, a kind of filtering technique is performed, which is called cross-correlation filter. The third kind of spectrum is the power spectrum of filtered sequence. It is shown that solar wind in the years during which it would seem in disorder both in general power spectrum and in maximum entropy spectrum now possesses the overweighted 13-day period after being filtered. >