地球主磁场电磁转矩导致的地球差异旋转  

The earth's differential rotation caused by the electromagnetic torque of the earth's main magnetic field

作　　者：邹润莉[1] 

机构地区：[1]长沙环境保护职业技术学院,长沙410004

出　　处：《地球物理学进展》2012年第3期977-987,共11页Progress in Geophysics

摘　　要：为探索驱动地球系统差异旋转的力源,选择整个地球作为研究对象,应用经典电磁学理论,分析地球固体介质中的电荷在地球主磁场中的运动特点,发现存在一个与地球自转方向相反的切向洛伦兹力.通过电荷与介质间的相互作用,切向洛伦兹力传递至介质迫使介质西漂.为探索地球差异旋转的规律,建立了地球薄圆筒圈层模型.应用经典物理学理论和方法推导出了地球主磁场电磁转矩及其产生的角加速度公式.研究得到四点主要结论:1)作用于半径不同的地球薄圆筒圈层的地球主磁场电磁转矩及其产生的角加速度绝对值不同:地轴及赤道附近圈层的小,其自转相对较快;半径等于3～(1/2)倍地球半径的薄圆筒圈层及其相邻圈层的大,其自转相对较慢.2)同一薄圆筒圈层中的差异旋转缘于介质的介电常数、阻力系数及质量密度的差异.3)地球差异旋转缘于地球的自转、正负电荷的非对等分布及介质的介电常数、阻力系数、质量密度的差异.4)地球差异旋转导致地壳运动,孕育地震,地球主磁场是地球差异旋转和地震孕育的敏感因子.As the earth＇s main magnetic field is stationary relative to the earth＇s axis,the earth autorotation drives the electrostatic charges to move along the vertical direction of the earth＇s main magnetic field, and causes charged particles subject to Lorentz force. According to the right-hand screw rule, the Lorentz force lies in meridian plane, perpendicular to the earth＇s rotation speed, with the directions of positively charged particles pointing to the earth＇s axis and the negatively charged to the opposite in normal phase of geomagnetic field, while in abnormal phase, they point to the opposite. This force is proportional to the earth＇s rotation speed and is referred to as normal Lorentz force. The normal Lorentz force forces the charges to drift along the normal and causes the normal drift velocity. Similarly, it is deduced that the Lorentz force, corresponding to the normal drift velocity of the charged particles, is always to the west along the tangent whether normal or abnormal phase of geomagnetic field. This force is proportional to the normal drift velocity and is referred to as tangent Lorentz force. The tangential Lorentz force causes charged particles to produce tangent acceleration,and thus forms westward drift which drives the solid medium containing charged particles drift westward. It hinders the earth＇s rotation that the torque of the tangential Lorentz force relative to the earth＇s axis,which is the electromagnetic torquen M of the earth＇s main magnetic field. This leads to the earth＇s rotation rate long-term slowdown in single-valued, as well as differential rotation of the earth. To explore the law of the earth＇s differential rotation, the whole earth was studied as the object and the earth＇s axis was as the central axis for the cylindrical coordinate system. With application of the classical physics theory and analyzing method,the formulas were deduced to calculate the rotary inertia y of thin cylinder in the earth＇s sphere, the electromagnetic torque M acting on thin

关 键 词：地球主磁场 电磁转矩 地球薄圆筒圈层模型 电源-电容器 角加速度 差异旋转 

分 类 号：P318[天文地球—固体地球物理学]