Determining the temporal dynamics of the solar a effect
Determining the temporal dynamics of the solar a effect
复制标题
确定太阳效应的时间动态
DOI：
10.1051/0004-6361/201219456
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发表时间：
2013
影响因子：
6.5
通讯作者：
Newton A
中科院分区：
文献类型：
--
作者：
Newton A
目的利用太阳活动的观测值来约束随机非线性发电机模型中与α效应有关的参数。方法通过计算观测太阳活动的概率分布函数(PDF)和我们对α−-Ω平均场发电机模型的模拟，进行全面的统计比较。所使用的观测数据是根据过去11 ，000年的C14数据在长时间尺度上推断的太阳活动的时间历史，以及在短时间尺度上对最近几年获得的1795−1995太阳黑子数的直接观测。对这些数据进行了蒙特卡罗模拟，得到了太阳活动在长时间尺度和短时间尺度上的概率分布函数。然后将这些PDF与我们的α−和Ω发电机模型的数值模拟预测的PDF进行比较，其中α被假设具有平均α0和波动α‘部分。结果通过改变波动τα的关联时间α’、波动幅度与平均ααR=√⟨αR2⟩/α20的比率(其中尖括号⟨⟩表示系综平均)以及极向和环向磁场的比率，我们表明，我们的随机发电机模型的结果可以匹配当τα∈为[22，44]年而αR∈为[0.21，0.24]时的太阳活动PDF。
AimsWe use observations of solar activity to constrain parameters relating to theαeffect in stochastic nonlinear dynamo models.MethodsThis is achieved through performing a comprehensive statistical comparison by computing probability distribution functions (PDFs) of solar activity from observations and from our simulation ofα− Ω mean field dynamo model. The observational data that are used are the time history of solar activity inferred for C14 data in the past 11 000 years on a long time scale and direct observations of the sun spot numbers obtained in recent years 1795−1995 on a short time scale. Monte Carlo simulations are performed on these data to obtain probability distribution functions (PDFs) of the solar activity on both long and short time scales. These PDFs are then compared with predicted PDFs from numerical simulation of ourα− Ω dynamo model, whereαis assumed to have both meanα0and fluctuatingα′ parts.ResultsBy varying the correlation timeταof fluctuatingα′, the ratio of the amplitude of the fluctuating to mean alpha αR= √⟨αr2⟩/α20(where angular brackets ⟨ ⟩ denote ensemble average), and the ratio of poloidal to toroidal magnetic fields, we show that the results from our stochastic dynamo model can match the PDFs of solar activity whenτα∈ [22,44] years withαR∈ [0.21,0.24].