检索结果-南通市图书馆

Studies of grand minima in sunspot cycles by using a flux transport solar dynamo model

Research in Astronomy and Astrophysics 2013年第11期13卷 1339-1357页

作者： bidya binay karak Arnab Rai Choudhuri Department of Physics Indian Institute of Science

We propose that grand minima in solar activity are caused by simultane- ous fluctuations in the meridional circulation and the Babcock-Leighton mechanism for the poloidal field generation in the flux transport dynamo model. We present the following results：（a） fluctuations in the meridional circulation are more effective in producing grand minima; （b） both sudden and gradual initiations of grand minima are possible; （c） distributions of durations and waiting times between grand minima seem to be exponential; （d） the coherence time of the meridional circulation has an effect on the number and the average duration of grand minima, with a coherence time of about 30 yr being consistent with observational data. We also study the occurrence of grand maxima and find that the distributions of durations and waiting times between grand maxima are also exponential, like the grand minima. Finally we address the question of whether the Babcock-Leighton mechanism can be operative during grand minima when there are no sunspots. We show that an a-effect restricted to the upper portions of the convection zone can pull the dynamo out of the grand minima and can match various observational requirements if the amplitude of this a-effect is suitably fine-tuned.

关键词： magnetic fields -- (magnetohydrodynamics:) MHD -- Sun: magneticfields -- (Sun:) sunspots

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Subcritical dynamo and hysteresis in a Babcock-Leighton type kinematic dynamo model

引用

Research in Astronomy and Astrophysics 2021年第10期21卷 250-256页

作者： Vindya Vashishth bidya binay karak Leonid Kitchatinov Department of Physics Indian Institute of Technology(BHU)Varanasi 221005India Institute of Solar-Terrestrial Physics SB RAS Lermontov Str.126A664033IrkutskRussia Pulkovo Astronomical Observatory Pulkovskoe Sh.65St.Petersberg196140Russia

In the Sun and Sun-like stars,it is believed that cycles of the large-scale magnetic field are produced due to the existence of differential rotation and helicity in the plasma flows in their convection zones(CZs).Hence,it is expected that for each star,there is a critical dynamo number for the operation of a large-scale *** a star slows down,it is expected that the large-scale dynamo ceases to operate above a critical rotation *** our study,we explore the possibility of the operation of the dynamo in the subcritical region using the Babcock–Leighton type kinematic dynamo *** some parameter regimes,we find that the dynamo shows hysteresis behavior,i.e.,two dynamo solutions are possible depending on the initial parameters—decaying solution if starting with weak field and strong oscillatory solution(subcritical dynamo)when starting with a strong ***,under large fluctuations in the dynamo parameter,the subcritical dynamo mode is unstable in some parameter ***,our study supports the possible existence of subcritical dynamo in some stars which was previously demonstrated in a mean-field dynamo model with distributedαand MHD turbulent dynamo simulations.

关键词： magnetic field Sun:activity Sun:magnetic fields stars:rotation stars:dynamo stars

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A possible explanation of the Maunder minimum from a flux transport dynamo model

引用

Research in Astronomy and Astrophysics 2009年第9期9卷 953-958页

作者： Arnab Rai Choudhuri bidya binay karak Department of Physics Indian Institute of ScienceBangalore-560012India

We propose that the poloidal field at the end of the last sunspot cycle before the Maunder minimum fell to a very low value due to fluctuations in the Babcock-Leighton process. With this assumption, a flux transport dynamo model is able to explain various aspects of the historical records of the Maunder minimum remarkably well by suitably choosing the parameters of the model to give the correct growth time.

关键词： Sun: activity -- Sun: magnetic fields -- sunspots

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：