Effects of lightning and sprites on the ionospheric potential, and threshold effects on sprite initiation, obtained using an analog model of the global atmospheric electric circuit
Effects of lightning and sprites on the ionospheric potential, and threshold effects on sprite initiation, obtained using an analog model of the global atmospheric electric circuit
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DOI：
10.1029/2009ja014758
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发表时间：
2010-06-22
影响因子：
2.8
通讯作者：
Odzimek, A.
中科院分区：
文献类型：
--
作者：
Rycroft, M. J.;Odzimek, A.
利用PSPICE电气工程软件建立了全球大气电路的定量模型。雷暴和带电的雨/阵雨云上方的电流(约1千伏)将电离层(假定为80公里高度的等电势表面)相对于地球表面的电势提高到约250千伏。循环是由流经陆地/海洋表面晴朗大气层的电流完成的，并向上到达云系。利用大气电导率分布模型，估算了正、负云地闪电对电离层电离层电势的影响。大的正CG放电产生一个超过击穿电场的电场，从电离层向下到类似74公里，从而形成光晕，柱状精灵，并在几毫秒后，从类似到67公里下降到类似55公里，在类似放电后60毫秒，一个“胡萝卜”精灵。估计了+CG放电超过阈值击穿电场或产生和维持负或正流光的阈值电场所需的回击电流和雷云电荷矩变化。在80千米高度击穿的数值分别为35千安和350摄氏度。公里)，海拔70公里处分别为45kA和360℃。区分柱状精灵和胡萝卜精灵的中层电场的不同时间和空间发展与最近观测到的最新推论一致。在高导电性的精灵中流动的电流使电离层电势降低了大约1V。
A quantitative model of the global atmospheric electric circuit has been constructed using the PSpice electrical engineering software package. Currents (similar to 1 kA) above thunderstorms and electrified rain/shower clouds raise the potential of the ionosphere (presumed to be an equipotential surface at 80 km altitude) to similar to 250 kV with respect to the Earth's surface. The circuit is completed by currents flowing down through the fair-weather atmosphere in the land/sea surface and up to the cloud systems. Using a model for the atmospheric conductivity profile, the effects of both negative and positive cloud-to-ground (CG) lightning discharges on the ionospheric potential have been estimated. A large positive CG discharge creates an electric field that exceeds the breakdown field from the ionosphere down to similar to 74 km, thereby forming a halo, a column sprite, and some milliseconds later, from similar to 67 km down to similar to 55 km at similar to 60 ms after the discharge, a "carrot" sprite. Estimates are made of the return stroke current and the thundercloud charge moment change of a +CG discharge required to exceed the threshold breakdown field, or the threshold field for creating and sustaining negative or positive streamers. The values for breakdown at 80 km altitude are 35 kA and 350 C. km, (Coulomb. kilometers), respectively, and those at 70 km altitude are 45 kA and 360 C. km, respectively. The different temporal and spatial developments of the mesospheric electric field distinguishing between column and carrot sprites agree with the latest deductions from recent observations. The current flowing in the highly conducting sprite reduces the ionospheric potential by similar to 1 V.