丁嘉威^1,,
王正涛^1,2,,,
詹文臻¹,
刘美琴¹
1. 武汉大学测绘学院, 武汉 430079
2. 武汉大学地球空间环境与大地测量教育部重点实验室, 武汉 430079

基金项目: 国家自然科学基金（41774019，41974007，41474018）和地球观测与时空信息科学国家测绘地理信息局重点实验室经费资助项目（2018：12）联合资助


详细信息

作者简介: 丁嘉威, 男, 1997年生, 在读硕士生, 主要从事固体地球物理学研究.E-mail: 786719044@qq.com

通讯作者: 王正涛, 男, 1976年生, 博士生导师, 教授, 主要从事固体地球物理学研究.E-mail: ztwang@whu.edu.cn

中图分类号: P318

收稿日期:2020-06-12
修回日期:2021-02-05
上线日期:2021-04-10

Influence of the driving mode of the finitely conducting inner core of the dynamo

DING JiaWei^1,,
WANG ZhengTao^1,2,,,
ZHAN WenZhen¹,
LIU MeiQin¹
1. School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China
2. Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan 430079, China


More Information

Corresponding author: WANG ZhengTao,E-mail:ztwang@whu.edu.cn

MSC: P318

--> Received Date: 12 June 2020
Revised Date: 05 February 2021
Available Online: 10 April 2021


摘要
摘要:本文以两种绝缘内核的发电机为基准，设置内核电导率与外核相同，选择了以固定速度超速旋转和在外核驱动下发生旋转的两种内核旋转模式，比较分析不同模型间的能量差异、磁场强度、磁雷诺数、磁极翻转频率和四个类地发电机参数.结果表明：对于弱偶极子发电机模型，有限导电内核的引入会对其偶极子强度的相对变化量造成较大影响，最高达103.00%；由外核驱动旋转的有限导电内核模型对于本文其他目标研究量所带来的影响比较小，均小于5%；而固定旋转速度的有限导电内核的模型对磁极翻转频率、赤道对称性和纬向性均存在较明显影响，最大变化量达124.62%.综合本文所选用的发电机模型的特征和数值分析结果，可以发现虽然由外核驱动旋转的有限导电内核模型其转速不可控且存在较大波动，但各物理量变化量与实际内核与外核的能量比更为接近，因此可以推断其驱动机制较自驱动模式更为合理可靠.
关键词: 有限导电内核/
超速旋转/
轴向偶极子强度/
磁极翻转频率

Abstract:In this study, two types of dynamo with an insulating inner core are taken as the basis, in which the inner core conductivity is set to be the same as the outer core. Two inner core rotation modes, super-rotation with a fixed speed and rotation under outer core drive, were chosen. Their energy difference, magnetic field strength, magnetic Reynolds number, and four Earth-like parameters among different models were compared and analyzed. The results show that for the dynamos with weak relative axial dipole power the introduction of the finitely conducting inner core will have a greater impact on the relative change in their relative axial dipole power, that is, up to 103.00%. The finitely conducting inner core driven by the outer core has little influence on other physical parameters, that is, all less than 5%. However, the models of the finitely conducting inner core with fixed super-rotation speed demonstrate an obvious influence on the frequency of magnetic polarity transition, equatorial symmetry, and zonality, with a maximum variation of 124.62%. Based on comprehensive analysis of the characteristics and numerical results of the dynamos selected in this study, it can be concluded that, although the rotation speed of the finitely conducting inner core driven by the outer core is uncontrollable and fluctuates greatly, the variation of each physical quantity is relatively close to the actual energy ratio of the inner and outer cores, therefore, it can also be inferred that its driving mechanism is more reasonable and reliable than that of the self-driving mode.
Key words:The finitely conducting inner core/
Super-rotation/
Relative axial dipole power/
Frequency of magnetic polarity transition



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