AI 中文总结
该研究利用ACE与Wind航天器数据，定量分析不同太阳风结构下L1点6项关键参数的去相关长度，发现整体太阳风速度相干性最强，ICME磁场相干性最优，SIR相干性较弱，为太阳风结构区分提供定量框架。
AI 中文摘要
理解太阳风等离子体和磁场属性的空间相干性，对于解释多航天器观测结果和表征日球层瞬变事件的大尺度结构至关重要。本研究利用ACE和Wind航天器的同步测量数据，针对瞬时分离距离，量化了6项关键太阳风参数的空间相关性，这些参数包括：行星际磁场分量、整体流速、质子数密度以及α粒子与质子的丰度比。分析分别针对背景太阳风、行星际日冕物质抛射（ICME）和流相互作用区（SIR）的时间间隔进行。采用指数函数对皮尔逊相关系数随距离的衰减进行建模，以推断特征去相关长度尺度。研究发现，整体太阳风速度在所有区域都是空间相干性最强的参数，而等离子体成分的相干性最弱。磁场相干性对太阳风结构表现出强依赖性：ICME呈现接近1的相关性和最大的磁场相干尺度，这与有组织的通量绳状构型一致；而SIR的相干性降低，尤其是南北向磁场分量，反映了压缩且湍流的等离子体。背景太阳风表现出中间行为，整体等离子体属性具有大尺度相干性，但磁场波动的相干长度较短。这些结果为基于空间相干性属性区分太阳风结构提供了定量框架，并对多点太阳风研究和空间天气应用具有重要意义。
英文摘要
Understanding the spatial coherence of solar wind plasma and magnetic field properties is essential for interpreting multi-spacecraft observations and for characterizing the large-scale structure of heliospheric transients. In this study, we quantify the spatial correlation of six key solar wind parameters - interplanetary magnetic field components, bulk flow speed, proton number density, and the alpha-to-proton abundance ratio - using simultaneous measurements from the ACE and Wind spacecraft as a function of their instantaneous separation distance. The analysis is performed separately for intervals of background solar wind, Interplanetary Coronal Mass Ejections (ICMEs), and Stream Interaction Regions (SIRs). The decay of the Pearson correlation coefficient with distance is modeled using an exponential function to infer characteristic de-correlation length scales. We find that the bulk solar wind speed is the most spatially coherent parameter in all regimes, while plasma composition exhibits the weakest coherence. Magnetic field coherence shows strong dependence on solar wind structure: ICMEs display near-unity correlations and the largest magnetic coherence scales, consistent with organized, flux-rope-like configurations, whereas SIRs exhibit reduced coherence - particularly in the north - south magnetic field component - reflecting compressed and turbulent plasma. The background solar wind exhibits intermediate behavior, with large-scale coherence in bulk plasma properties but shorter coherence lengths in magnetic fluctuations. These results provide a quantitative framework for distinguishing solar wind structures based on their spatial coherence properties and have important implications for multi-point solar wind studies and space weather applications.
Commentsaccepted for publication in Advances in Space Research
