Understanding Solar Cycle Variability
Understanding Solar Cycle Variability
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DOI：
10.3847/1538-4357/aa767a
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发表时间：
2017-05
期刊：
影响因子：
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通讯作者：
R. Cameron;M. Schussler
中科院分区：
文献类型：
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作者：
R. Cameron;M. Schussler
太阳磁场活动的水平，如太阳黑子的数量和日冕中的高能事件所表明的，在很大的时间尺度范围内变化。最突出的是11年的太阳周期，它在较长的时间尺度上有明显的调制。根据发电机理论，结合过去太阳活动的经验结果和类太阳恒星的类似现象，我们表明太阳周期的可变性基本上可以用受随机噪声影响的弱非线性极限环来理解。与太阳周期的临时“玩具模型”相比，这导致了一个通用的标准形式模型，其参数都受到观测的限制。该模型再现了在几十年到几千年的时间尺度上变化的太阳活动的特征，包括极低活动（极大极小期）的发生和长时间的统计。与babcock - leighton型发电机模型的结果比较，证实了正态方法的有效性。
The level of solar magnetic activity, as exemplified by the number of sunspots and by energetic events in the corona, varies on a wide range of timescales. Most prominent is the 11-year solar cycle, which is significantly modulated on longer timescales. Drawing from dynamo theory, together with the empirical results of past solar activity and similar phenomena for solar-like stars, we show that the variability of the solar cycle can be essentially understood in terms of a weakly nonlinear limit cycle affected by random noise. In contrast to ad hoc “toy models” for the solar cycle, this leads to a generic normal-form model, whose parameters are all constrained by observations. The model reproduces the characteristics of the variable solar activity on timescales between decades and millennia, including the occurrence and statistics of extended periods of very low activity (grand minima). Comparison with results obtained with a Babcock–Leighton-type dynamo model confirm the validity of the normal-mode approach.