Abstract A model of electric discharges at mesospheric altitudes has been developed to explain the nature of optical flashes/transient atmospheric events (TAEs) observed aboard the Russian microsatellites “Universitetsky-Tatyana-1”, “Universitetsky-Tatyana-2” and “Vernov”. The model is based on assumption that large-scale areas with a low space charge density and a low electric breakdown threshold can occur in the mesosphere thereby producing electric discharges between the charged areas. Variations in the number densities of electrons and ions in the discharge channel connecting these areas are described by kinetic equations, in which spatial derivatives are disregarded. The discharge parameters, such as mobility of charged particles, rate of ionization and rate electron attachment to neutral molecules are assumed to depend on altitude in the atmosphere. Numerical simulation and analytical solutions of the basic equation set make it possible to analyze the time dependences of electric field, conductivity, current and number densities of electrons and ions in the discharge channel at various altitudes in the atmosphere. Theoretical estimates of the TAEs parameters are best suited to the onboard observations under assumptions that, first, the charged areas of 10 − 15 km in size are situated at altitudes of 60 − 70 km and, second, their total charge is about 1 C. The theory predicts that the energy dissipated during a single electric discharge under these parameters can reach a value from tenths to several MJ while the discharge duration can be on the order of several milliseconds.

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关于在 Universitetsky-Tatyana 和 Vernov 卫星上观察到的光学闪光的性质

摘要 为了解释在俄罗斯微型卫星“Universitetsky-Tatyana-1”、“Universitetsky-Tatyana-2”和“Vernov”上观测到的光学闪光/瞬态大气事件 (TAE) 的性质，已经开发了一个中间层高度的放电模型。 . 该模型基于这样的假设，即在中间层可能出现具有低空间电荷密度和低电击穿阈值的大尺度区域，从而在带电区域之间产生放电。连接这些区域的放电通道中电子和离子数量密度的变化由动力学方程描述，其中忽略空间导数。放电参数，例如带电粒子的迁移率，假定电离率和电子附着于中性分子的速率取决于大气中的高度。基本方程组的数值模拟和解析解使得可以分析大气中不同高度的放电通道中的电场、电导率、电流和电子和离子的数量密度的时间依赖性。TAEs 参数的理论估计最适合机载观测，假设首先，10 - 15 公里大小的带电区域位于 60 - 70 公里的高度，其次，它们的总电荷约为 1 C。