| 电导率日夜不均匀性对磁层-电离层电场耦合过程的影响 |
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| 引用本文： | 资民筠,沈长寿.电导率日夜不均匀性对磁层-电离层电场耦合过程的影响[J].地球物理学报,1986,29(3):207-219. |
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| 作者姓名： | 资民筠 沈长寿 |
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| 作者单位： | 北京大学地球物理系 |
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| 摘 要： | 本文用随时间变化的对流模式,讨论了电导率日夜不均匀性对磁层-电离层耦合过程及大尺度场向电流日变化形态的影响,以Senior-Blanc随时间变化的简单模式为基础,计入电导率日夜变化加以发展,对驱动势随时间变化为阶梯函数的情况进行了讨论。修正模式表明电导率日夜不均匀性对磁层-电离层弛豫过程产生影响,在不同地方时,二区场向电流发展状况不同,达到平衡时间也各异。在某些条件下,中午前后甚至可能达不到平衡。模式计算给出的电位及场向电流图象与观测基本特点相符。这说明S-B模式反映了电场耦合中的主要物理过程,也表明电离层电导率日夜变化的调制作用。
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| 关 键 词： | 场向电流 电离层电场 磁层 电离层电导率 驱动势 不均匀性 耦合过程 时角 B模式 赤道环 |
| 收稿时间： | 1985-06-12 |
THE EFFECT OF THE DAY-NIGHT IONOSPHERIC CONDUCTIVITY GRADIENT ON THE MAGNETOSPHERE-IONOSPHERE COUPLING |
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| ZI MIN-YUN,SHEN CHANG-SHOU.THE EFFECT OF THE DAY-NIGHT IONOSPHERIC CONDUCTIVITY GRADIENT ON THE MAGNETOSPHERE-IONOSPHERE COUPLING[J].Chinese Journal of Geophysics,1986,29(3):207-219. |
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| Authors: | ZI MIN-YUN SHEN CHANG-SHOU |
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| Institution: | Geophysical Department, Peking University, Beijing |
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| Abstract: | A time-dependent analytical model has been used to study the effect of the day-night ionospheric conductivity gradient on the magnetosphere-ionosphere coupling. The basic idea is the same as that of Senior-Blanc's model. The mathematical difficulties caused by the conductivity gradient have been overcome and the analytical solutions of the model have been deduced for a kind of finite driving (potential φ0, which is applied to a magnetosphere initially at rest and maintains invariant later on. The results from the model calculation show that the time constant of the evolution toward steady state varies with local time when the conductivities are day-night inhomogeneous. Under some special conditions the steady state may even be unattainable within a certain time period. The feature predicted by the model calculculation for both the field-aligned currents and the potential distribution is in reasonable agreement with the statistical picture from measurements. This not only supports the linear approximation of the ionosphere/mag-netosphere circuit suggested by C. Senior and M. Blanc, but also confirms the modulation effect of the day-night conductivity gradient on the coupling circuit. |
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