Solar Wind Plasma Parameter Variability Across Solar Cycles 23 and 24: From Turbulence to Extremes
Solar Wind Plasma Parameter Variability Across Solar Cycles 23 and 24: From Turbulence to Extremes
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第 23 和 24 个太阳周期的太阳风等离子体参数变化：从湍流到极端
DOI：
10.1002/2017ja024412
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Tindale E
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文献类型：
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作者：
Tindale E
太阳风变率跨越了广泛的幅度和时间尺度，从湍流波动到11年太阳周期。本文采用数据分位数-分位数（DQQ）方法，对美国宇航局/美国宇航局第23和第24太阳周期的观测数据进行分析，研究各周期最大值和最小值的独特性如何体现在快、慢太阳风中等离子体参数统计分布的变化中。DQQ方法允许我们区分分布的两个不同组成部分：核心区域只是在其时刻跟踪太阳周期，但对太阳风状态或每个周期的特定活动几乎没有敏感性。这将与一个潜在的原位过程相一致，例如湍流推动波动演变到外部尺度。相反，该分布的尾部分量对第23和第24周期的最大值和最小值的差异以及太阳风的快慢状态都很敏感。尾巴部分在太阳活动周期中以这样一种方式变化，以保持恒定的功能形式，只有它的矩随太阳活动而变化。最后，在分离出核心区后，我们对每一种太阳风状态下太阳周期的对数正态性进行了检验，发现对数正态性对慢风的统计量的描述比快风的统计量更稳健；然而，在这两种状态下，在太阳活动极大期，拟合优度显著降低。
Solar wind variability spans a wide range of amplitudes and timescales, from turbulent fluctuations to the 11 year solar cycle. We apply the data quantile‐quantile (DQQ) method to NASA/Wind observations spanning solar cycles 23 and 24, to study how the uniqueness of each cycle maximum and minimum manifests in the changing statistical distribution of plasma parameters in fast and slow solar wind. The DQQ method allows us to discriminate between two distinct components of the distribution: the core region simply tracks the solar cycle in its moments but shows little sensitivity to solar wind state or the specific activity of each cycle. This would be consistent with an underlying in situ process such as turbulence driving the evolution of fluctuations up to an outer scale. In contrast, the tail component of the distribution is sensitive both to the differences between the maxima and minima of cycles 23 and 24, and the fast or slow state of the solar wind. The tail component varies over the solar cycle in such a way as to maintain a constant functional form, with only its moments varying with solar activity. Finally, after isolating the core region of the distribution, we test its lognormality over the solar cycle in each solar wind state and find the lognormal provides a more robust description of the statistics in slow wind than fast; however, in both states the goodness of fit is significantly reduced at solar maximum.