Buoyancy-induced time delays in Babcock-Leighton flux-transport dynamo models
Buoyancy-induced time delays in Babcock-Leighton flux-transport dynamo models
复制标题
Babcock-Leighton 通量输运发电机模型中浮力引起的时间延迟
DOI：
10.1051/0004-6361/201014455
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发表时间：
2010
影响因子：
6.5
通讯作者：
Jouve L
中科院分区：
文献类型：
--
作者：
Jouve L
背景太阳是一颗磁星，其周期性活动被认为与内部发电机机制有关。不同复杂程度的数值建模的结合是研究此类复杂动力过程的高效而准确的工具。目的我们通过更准确地模拟极向场的表面源项，研究磁浮力过程在 2D Babcock-Leighton 发电机模型中的作用。方法为此，我们在平均场模型中重新引入上升非线性演化的完整 3D MHD 计算结果 对流壳中的通量管。更具体地说，修改了巴布科克-莱顿源项，以考虑到环形结构从对流区底部到太阳表面的上升时间引入的延迟。结果我们发现，即使考虑强且快速上升的通量管，方程中引入的时间延迟也会产生周期幅度的大时间调制。太阳周期的非周期性调制出现在非线性系统典型的一系列倍周期分岔之后。发现即使是小延迟也会产生强烈的影响，这是由于延迟对对流区底部磁场强度的依赖性，当时间延迟保持恒定时，调制要少得多。我们没有发现对周期周期有任何重大影响，除非人为地强加延迟。结论这里揭示了太阳周期变化的一个可能的新起源。这种调制的活动和由此产生的蝴蝶图比标准 Babcock-Leighton 模型产生的结果更符合观察结果。
ContextThe Sun is a magnetic star whose cyclic activity is thought to be linked to internal dynamo mechanisms. A combination of numerical modelling with various levels of complexity is an efficient and accurate tool to investigate such intricate dynamical processes.AimsWe investigate the role of the magnetic buoyancy process in 2D Babcock-Leighton dynamo models, by modelling more accurately the surface source term for poloidal field.MethodsTo do so, we reintroduce in mean-field models the results of full 3D MHD calculations of the non-linear evolution of a rising flux tube in a convective shell. More specifically, the Babcock-Leighton source term is modified to take into account the delay introduced by the rise time of the toroidal structures from the base of the convection zone to the solar surface.ResultsWe find that the time delays introduced in the equations produce large temporal modulation of the cycle amplitude even when strong and thus rapidly rising flux tubes are considered. Aperiodic modulations of the solar cycle appear after a sequence of period doubling bifurcations typical of non-linear systems. The strong effects introduced even by small delays is found to be due to the dependence of the delays on the magnetic field strength at the base of the convection zone, the modulation being much less when time delays remain constant. We do not find any significant influence on the cycle period except when the delays are made artificially strong.ConclusionsA possible new origin of the solar cycle variability is here revealed. This modulated activity and the resulting butterfly diagram are then more compatible with observations than what the standard Babcock-Leighton model produces.
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DOI：
10.1016/0167-2789(83)90279-8
发表时间：
1983
期刊：
Physica D: Nonlinear Phenomena
影响因子：
--
作者：
E. Knobloch;N. Weiss
通讯作者：
N. Weiss
影响因子：
4.9
作者：
Fan, Y.
通讯作者：
Fan, Y.
非线性α效应发电机方程的数值解
影响因子：
3.7
作者：
M. Proctor
通讯作者：
M. Proctor
恒星发电机的调制和对称性变化
DOI：
10.1046/j.1365-8711.1998.01572.x
发表时间：
1998
影响因子：
4.8
作者：
E. Knobloch;S. Tobias;N. Weiss
通讯作者：
N. Weiss
DOI：
10.1111/j.1365-2966.2005.09741.x
发表时间：
2006
影响因子：
4.8
作者：
F. Cattaneo;N. Brummell;Kelly S. Cline
通讯作者：
Kelly S. Cline