Permutation Entropy and Complexity Analysis of Large-scale Solar Wind Structures and Streams
Annales Geophysicae(2024)
摘要
In this work, we perform a statistical study of magnetic field fluctuations
in the solar wind at 1 au using permutation entropy and complexity analysis,
and the investigation of the temporal variations of the Hurst exponents. Slow
and fast wind, magnetic clouds, interplanetary coronal mass ejection
(ICME)-driven sheath regions and slow-fast stream interaction regions (SIRs)
have been investigated separately. Our key finding is that there are
significant differences in permutation entropy and complexity values between
the solar wind types at larger timescales and little difference at small
timescales. Differences become more distinct with increasing timescale,
suggesting that smaller-scale turbulent features are more universal. At larger
timescales, the analysis method can be used to identify localized spatial
structures. We found that except in magnetic clouds, fluctuation are largely
anti-persistent and that the Hurst exponents, in particular in compressive
structures (sheaths and SIRs) exhibit a clear locality. Our results shows that,
in all cases apart from magnetic clouds at largest scales, solar wind
fluctuations are stochastic with the fast wind having the highest entropies and
low complexities. Magnetic clouds in turn exhibit the lowest entropy and
highest complexity, consistent with them being coherent structures in which the
magnetic field components vary in an ordered manner. SIRs, slow wind and ICME
sheaths are intermediate to magnetic clouds and fast wind, reflecting the
increasingly ordered structure. Our results also indicate that permutation
entropy - complexity analysis is a useful tool for characterizing the solar
wind and investigating the nature of its fluctuations.
更多查看译文
AI 理解论文
溯源树
样例
![](https://originalfileserver.aminer.cn/sys/aminer/pubs/mrt_preview.jpeg)
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要