arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1702.03149astro-ph.SR
收藏

太阳活动周期23和24之间最小深度的日震透视

A Helioseismic Perspective on the Depth of the Minimum Between Solar Cycles 23 and 24

A. -M. Broomhall

摘要:

在第23和24周之间观测到的太阳活动周期最小值通常被认为是异常深和长的。紧随这一最低值之后的是近代历史上最小的振幅周期之一。我们用日震学对这一最小值进行了深入的分析。我们使用全球振荡网络组(GONG)的数据来证明日震振荡的频率是太阳磁场的敏感探测器:发现日震振荡的频率在第23周之后的极小期系统地低于之前的极小期。这种差异在统计上是显著的,可能表明太阳的全球磁场在第23周较弱。至少在周期23之后。两个最小值之间的振荡频率的偏移的大小取决于振荡的频率,并且采用与当将周期最大值处的频率与周期最小值频率进行比较时观察到的频率依赖性相同的函数形式。这意味着相同的近地表磁扰动是负责的。最后,我们确定第23个周期之前的最小值和之后的最小值之间的平均磁场差约为1G。

英文摘要:

The solar-activity-cycle minimum observed between Cycles 23 and 24 is generally regarded as being unusually deep and long. That minimum is being followed by one of the smallest amplitude cycles in recent history. We perform an in-depth analysis of this minimum with helioseismology. We use Global Oscillation Network Group (GONG) data to demonstrate that the frequencies of helioseismic oscillations are a sensitive probe of the Sun's magnetic field: The frequencies of the helioseismic oscillations were found to be systematically lower in the minimum following Cycle 23 than in the minimum preceding it. This difference is statistically significant and may indicate that the Sun's global magnetic field was weaker in the minimum following Cycle 23. The size of the shift in oscillation frequencies between the two minima is dependent on the frequency of the oscillation and takes the same functional form as the frequency dependence observed when the frequencies at cycle maximum are compared with the cycle-minimum frequencies. This implies that the same near-surface magnetic perturbation is responsible. Finally, we determine that the difference in the mean magnetic field between the minimum preceding Cycle 23 and that following it is approximately 1G.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑