电离层等离子体交换不稳定性与大气重力波的耦合

COUPLING BETWEEN ATMOSPHERIC GRAVITY WAVES AND PLASMA INTERCHANGE INSTABILITY IN THE IONOSPHERE

研究了赤道电离层等离子体交换不稳定性和大气重力波的耦合性质。如果没有外部扰动的影响，非线性效应使交换不稳定性饱和在一个很小的幅度上。在适当的条件下，重力波能触发交换不稳定性。如果重力波的幅度足够大，所触发的交换不稳定性的扰动幅度能达到５０％甚至更大，产生等离子体泡，本文的理论揭示了电离层大尺度扩展Ｆ的产生机制，可以解释许多重要的电离层观测现象。

Coupling between atmospheric gravity waves and plasma interchange instabilityin the equatorial ionosphere is studied.The interchange instability is saturated at asmall amplitude by nonlinear effects if there are not any exterrial geophysical distu- rbances to influence it.It is shown that the gravity waves can initiate the intercha-nge instability under some conditions.The initiated instability grows to an amplitu-de of 50% even larger and forms plasma bubbles if the amplitude of the seed gra-vity waves is large enough.The present theory shows physical mechanism for produ- cing large scale equatorial spread F and explains a lot of ionospheric observations.