| 旋转分层导电流体的双扩散磁流体动力学不稳定性 |
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| 引用本文： | 马石庄.旋转分层导电流体的双扩散磁流体动力学不稳定性[J].地球物理学报,1993,36(5):579-588. |
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| 作者姓名： | 马石庄 |
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| 作者单位： | 中国科学院地球物理研究所, 北京 100101;中国科学院测量与地球物理研究所动力大地测量学开放研究实验室, 武汉 430077 |
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| 摘 要： | 本文研究了双扩散效应对处于地球物理极限q→0条件下旋转分层导电流体的磁流体动力学（MHD）不稳定性的影响。研究发现,只要|RS|足够大,对流总能在流体静力稳定分层的导电流体中发展。当磁场作用较弱,即Λ～Ο（1）时,对所有可能的角向波数m优先发展的是双扩散不稳定性。当Rs>0时,流体中发生几乎不变的“指状”对流。当Rs<0时,流体中发生缓慢东向运行的“扩散”振荡。当磁场作用较强,即Λ≥ΛM时,与原始Soward模式类似,优先发展的仅是m=1磁力驱动不稳定性,并东向运行,但双扩散效应使得正RT不稳定性与负RT不稳定性间的对称性破缺。
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| 关 键 词： | 导电流体 双扩散对流 核幔边界 |
| 收稿时间： | 1992-04-09 |
DOUBLE-DIFFUSIVE AND MHD INSTABILITIES IN A ROTATING STRATIFIED CONDUCTING FLUID LAYER |
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| MA SHI-ZHUANG.DOUBLE-DIFFUSIVE AND MHD INSTABILITIES IN A ROTATING STRATIFIED CONDUCTING FLUID LAYER[J].Chinese Journal of Geophysics,1993,36(5):579-588. |
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| Authors: | MA SHI-ZHUANG |
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| Institution: | Institute of Geophysics, Academia Sinica, Beijing 100101 |
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| Abstract: | The role that double-diffusive effect measured as the compositional Rayleigh number Rs plays in the magnetohydrodynamic instabilities of the modified Soward's model of a routing stratified fluid layer in the geophysical limite 9→0 is investigated,in which q is the ratio of thermal and magnetic diffusiviues.It is found that the convection is almost always developed in the hydrostatically stable stratified fluid layer on condition that R,is large enough.The double-diffusive instability is predominated when the magnetic filed characterised by Chandrasenhkar number ∧is weak,or ∧-O （1）,which takes the form of either quasis-steady "fingering" convection for Rs>0 or slow eastward propagating "diffusive" oscillation for Rs<0 and exists for all the mode m.When the magnetic field is strong,i.e.∧≥∧M,the double-diffusive stability is replaced by the magnetic driven instability which propagates eastward and exists only for the mode m=1 in a similar way to the prime Soward's model,but the symmetry between the positive RT instability and negtive RT instability is broken by the double-diffusive effect,in which RT is the thermal Rayleigh number. |
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| Keywords: | Conducting fluid Double-diffusive convection Earth's core-mantle boundary |
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