大气重力波产生大尺度赤道扩展F的理论

本文提出了大气重力波触发Ｒａｙｌｅｉｇｈ－Ｔａｙｌｏｒ不稳定性并导致大尺度赤道扩展Ｆ的理论．重力波作为外部扰动派触发等离子体扰动，这种扰动在Ｒａｙｌｅｉｇｈ－Ｔａｙｌｏｒ不稳定性的作用下继续增长，经过４００ｓ扰动幅度就能增长到５０％，经过７００ｓ后幅度趋近１００％，即为完全的等离子体泡．由于Ｅ区的影响，赤道扩展Ｆ主要出现于晚上．本文的理论阐明了重力波与Ｒａｙｌｅｉｇｈ－Ｔａｙｌｏｒ不稳定性相互作用的性质，揭示了大尺度赤道扩展Ｆ的产生机制．

A THEORY OF LARGE SCALE EQUATORIAL SPREAD F INITIATED BY ATMOSPHERIC GRAVITY WAVES

It Is shown in the present paper that atmospheric gravity waves can initiate the Rayleigh-Taylor instability and result in large scale equatorial spread F irregularities and plasma bubbles.The plasma perturbations initiated by external gravity waves continue to grow under the influence of Rayleigh-Taylor instability. For reasonable parameters of gravity waves and ionospheric plasma,the amplitude of the perturbations can reach 50%at 400s and approach 100% at 700s,implying complete plasma bubbles. Due to the conducting E region,the growth rate of the initiaed Rayleigh-Taylor instability is low during daytime.Consequently, the spread F appears mainly at night.The present theory demonstrates the possibility that large scale spread F irregularities are initiated by gravity waves with the Rayleigh-Taylor instability as an intermediate process. The theoretical results of this paper can explain reasonably the observations of spread-F associated with gravity waves.