A mathematical model is constructed of the equatorial electrojets flowing in the ionosphere which are generated by thunderstorms occurring at low latitudes. We use the narrow definition of the global electric circuit (GEC) that includes only atmospheric and ionospheric electric fields and currents generated by thunderstorms, and ignores the contributions of all ionospheric and magnetospheric generators. The ionospheric currents which distribute charges from the thunderstorm areas to the fair weather parts of the Earth are largest in the vicinity of the geomagnetic equator. They form the specific electrojets discussed here which are in addition to the electrojets formed by the wind dynamo. A model of the ionospheric potential which drives these currents was developed earlier and this is suitably modified here. We use an empirical model of the diurnal variation of the number of lightning strikes to define the currents up to the ionosphere from the main thunderstorm areas. A two-dimensional approximation of the ionospheric conductor is based on its high conductivity along the magnetic field. The Pedersen and Hall conductivity distributions are calculated using empirical ionospheric models; the Pedersen and Hall conductances are calculated by integration along magnetic field lines and these are used in the 2-D model of the ionospheric conductor. The spatial distributions of the ionospheric electric fields and currents are obtained by numerical solution of the 2-D ionospheric current continuity equation. The positions and the directions of the electrojets are defined by the global distribution of the main thunderstorm areas, as well as of the ionospheric conductivity, and so they strongly vary with Universal Time. As far as the generation of the equatorial electrojets is concerned, the African and Asian thunderstorm areas are more effective than the American ones since they are closest to the geomagnetic equator. There are day-time electrojets, the strength of which may be up to $175$ A, and night-time ones (of up to $60$ A), while the total current flowing in the GEC is not larger than $1400$ A at any moment of time in our model. Usually the electrojets are a few times weaker in the night-time ionosphere because of its smaller conductivity. The equatorial electrojets of the GEC thus produce magnetic perturbations on the ground, which are in the $0.1$ nT range, while there are one hundred times stronger, wind dynamo-driven electrojets and other larger, space weather-associated magnetic perturbations. Nevertheless, using their specific features these magnetic perturbations could be measured, especially at the night-time geomagnetic equator when and where they are not so disguised by other ionospheric currents.

数学模型是由在电离层中流动的赤道电射流构建的，这些电射流是由发生在低纬度地区的雷暴产生的。我们使用全球电路 (GEC) 的狭义定义，该定义仅包括由雷暴产生的大气和电离层电场和电流，而忽略了所有电离层和磁层发生器的贡献。将电荷从雷暴区分配到地球上晴朗天气部分的电离层电流在地磁赤道附近最大。除了风力发电机形成的电喷之外，它们还形成了这里讨论的特定电喷。驱动这些电流的电离层电势模型是较早开发的，这里进行了适当的修改。我们使用雷击次数的日变化经验模型来定义从主要雷暴区到电离层的电流。电离层导体的二维近似基于其沿磁场的高电导率。Pedersen 和 Hall 电导率分布是使用经验电离层模型计算的；佩德森电导和霍尔电导是通过沿磁场线积分计算的，它们用于电离层导体的二维模型。电离层电场和电流的空间分布是通过二维电离层电流连续性方程的数值解获得的。电射流的位置和方向由主要雷暴区的全球分布决定，以及电离层电导率的变化，因此它们随世界时变化很大。就赤道电射流的产生而言，非洲和亚洲的雷暴区距离地磁赤道最近，比美洲雷暴区更有效。有白天的电喷，其强度可能高达$175$ A，和夜间的（最多 $60$ A)，而流经 GEC 的总电流不大于 $1400$A 在我们模型中的任何时刻。通常电射流在夜间电离层中要弱几倍，因为它的电导率较小。GEC 的赤道电射流因此在地面上产生磁扰动，它们在$0.1$nT 范围，虽然有强一百倍的风力发电机驱动的电喷气机和其他更大的空间天气相关磁扰动。然而，利用它们的特定特征，可以测量这些磁扰动，特别是在夜间地磁赤道，何时何地它们不会被其他电离层电流掩盖。