COUPLING BETWEEN ATMOSPHERIC GRAVITY WAVES AND PLASMA INTERCHANGE INSTABILITY IN THE IONOSPHERE
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 equatorial ionosphere is studied. The interchange instability is saturated at a small amplitude by nonlinear effects if there are not any external geophysical distu-rbances to influence it. It is shown that the gravity waves can initiate the interchange instability under some conditions. The initiated instability grows to an amplitude of 50% even larger and forms plasma bubbles if the amplitude of the seed ,gravity waves is large enough. The present theory shows physical mechanism for producing large scale equatorial spread F and explains a lot of ionospheric observations.