Relative occurrence rates and connection of discrete frequency oscillations in the solar wind density and dayside magnetosphere
Relative occurrence rates and connection of discrete frequency oscillations in the solar wind density and dayside magnetosphere
复制标题
DOI：
10.1029/2008ja013334
复制
发表时间：
2009
影响因子：
--
通讯作者：
N. Viall;L. Kepko;H. Spence
中科院分区：
文献类型：
--
作者：
N. Viall;L. Kepko;H. Spence
[1]本文分析了f = 0.5-5.0 mHz范围内周期性太阳风数密度结构和日侧磁层振荡的统计显著视频率的发生分布。使用11年（1995-2005年）的太阳风数据，我们确定了所有的光谱峰值，通过幅度测试和谐波F测试在95%的置信水平，在6小时的数据段。我们发现某些离散频率，特别是f = 0.7，1.4，2.0和4.8 mHz，在这11年中比其他频率更频繁地出现。我们重复分析了10年（1996-2005年）观测到的日侧磁层离散振荡数据。我们发现某些频率，特别是f = 1.0，1.5，1.9，2.8，3.3和4.4 mHz，在这10年中比其他频率更频繁地出现。磁层发生分布中发现的许多增强与太阳风中发现的增强相似。最后，我们计算了相同的离散频率的次数被确定为统计上显着使用我们的两个光谱测试相应的太阳风和磁层6小时的时间序列。我们发现，在54%的太阳风数据段中，我们确定了一个谱峰，至少有一个相同的离散频率在相应的磁层数据段中具有统计学意义。我们的研究结果认为，在太阳风数密度，直接驱动全球磁层振荡在相同的离散频率的固有表观频率的存在，虽然磁层也通过其他物理机制振荡。
[1] We present an analysis of the occurrence distributions of statistically significant apparent frequencies of periodic solar wind number density structures and dayside magnetospheric oscillations in the f = 0.5–5.0 mHz range. Using 11 years (1995–2005) of solar wind data, we identified all spectral peaks that passed both an amplitude test and a harmonic F test at the 95% confidence level in 6-hour data segments. We find that certain discrete frequencies, specifically f = 0.7, 1.4, 2.0, and 4.8 mHz, occur more often than do other frequencies over those 11 years. We repeat the analysis on discrete oscillations observed in 10 years (1996–2005) of dayside magnetospheric data. We find that certain frequencies, specifically f = 1.0, 1.5, 1.9, 2.8, 3.3, and 4.4 mHz, occur more often than do other frequencies over those 10 years. Many of the enhancements found in the magnetospheric occurrence distributions are similar to those found in the solar wind. Lastly, we counted the number of times the same discrete frequencies were identified as statistically significant using our two spectral tests on corresponding solar wind and magnetospheric 6-hour time series. We find that in 54% of the solar wind data segments in which we identified a spectral peak, at least one of the same discrete frequencies was statistically significant in the corresponding magnetospheric data segment. Our results argue for the existence of inherent apparent frequencies in the solar wind number density that directly drive global magnetospheric oscillations at the same discrete frequencies, although the magnetosphere also oscillates through other physical mechanisms.