AI 中文总结
本研究利用帕克太阳探测器1至19次飞掠数据，探究平均时间尺度对太阳风阿尔文马赫数及湍流特性表征的影响，发现亚阿尔文区间分布对合适平均尺度不敏感，磁涨落能量随平均窗口增大而增加，相关时间随日心距离和MA减小而缩短，明确了选择物理意义背景对湍流参数表征的重要性。
AI 中文摘要
太阳风测量中的平均技术长期以来一直是争论的主题。利用帕克太阳探测器（Parker Solar Probe, PSP）第1至19次飞掠的观测数据，我们研究了平均时间尺度如何影响阿尔文转变过程中湍流特性的表征。我们计算了不同平均区间内的滚动平均阿尔文马赫数，并将其与转向（switchbacks）、磁涨落能量和相关时间进行分析。我们发现亚阿尔文区间的分布对经审慎选择的平均尺度相对不敏感；相比之下，磁涨落能量随平均窗口增大而系统性增加，同时在阿尔文转变过程中保持一致的分布。我们进一步表明，有效磁相关时间随日心距离和阿尔文马赫数（MA）的减小而缩短，当MA接近1时达到几分钟的量级。这些结果表明，为湍流参数（如相关尺度）选择具有物理意义的背景至关重要，且这会对太阳风的表征产生影响。
英文摘要
Averaging techniques in solar wind measurements have been a longstanding subject of debate. Using Parker Solar Probe (PSP) observations from encounters 1 to 19, we investigate how averaging timescales influence the characterization of turbulent properties across the Alfvenic transition. We compute the rolling mean Alfven Mach number over various averaging intervals, which are then analyzed against switchbacks, magnetic fluctuation energy, and correlation time. We find that the distribution of subAlfvenic intervals is relatively insensitive to judiciously-chosen averaging scales. In contrast, magnetic fluctuation energies increase systematically with larger averaging window, while maintaining a consistent profile across the Alfven transition. We further show that the effective magnetic correlation time decreases with decreasing heliocentric distance and MA, reaching values of several minutes approaching MA =1. These results demonstrate the importance of choosing physically meaningful backgrounds for turbulence parameters, such as the correlation scales, and their impacts on characterizing the solar wind.
Comments15 pages, 5 figures
