大气重力波产生的大尺度赤道电离层扰动

IONOSPHERIC DISTURBANCES PRODUCED BY ATMOSPHERIC GRAVITY WAVES IN THE EQUATORIAL F REGION

本文研究了大气重力波产生的大尺度赤道电离层扰动的性质．当重力波的传播方向与磁场方向倾斜相交时，重力波在Ｆ区产生行进电离层扰动．当重力波垂直于磁场传播时，能触发等离子体Ｒａｙｌｅｉｇｈ－Ｔａｙｌｏｒ不稳定性，形成大尺度赤道扩展Ｆ不均匀体．重力波引起的扩展Ｆ主要出现于晚上，行进电离层扰动则可能出现于任何时间．本文建立了行进电离层扰动和大尺度赤道扩展Ｆ的统一理论模型，深入全面地揭示了电离层扰动的性质．

Properties of large scale equatorial ionospheric disturbances produced by atmospheric gravity waves are studied.When propagating in a direction oblique to the magnetic field, gravity waves cause motions of ionization by ion-neutral collisions and produce travelling ionospheric disturbances(TIDs)in the F region.When propagating perpendicular to the magnetic field,gravity waves can generate polarization electric fields,initiate the plasma Rayleigh-Taylor instability,and result in large scale equatorial spread F(ESF)irregularities.The equatorial spread F initiated by gravity waves occurs mainly at night.Howerver,TIDs can occur at any time.It is shown that TIDs and large scale ESF irregularities are due to evolutions of ionospheric perturbations produced by gravity waves under different conditions.A model of unified theoly of the TIDs and large scale ESF irregularities associated with gravity waves is proposed in the present paper.