The Thunderstorm System as AC Circuit
The model is referred to the investigation of dynamical behavior of the normal bipolar thunderstorm system during all evolution period: development stage, mature or lightning stage and decay. The core of the model is simplification of a real thunderstorm system (TS) as a RC electric circuit. That is an opposite approach in comparison with modeling TS as two point charges, 1. Basic elements of our model are RC chains and current sources. All calculations have been made in cylindrical symmetry.Number of elements in the model is determined by the spatial division of TS to several cells with different physical properties. We suppose that TS consists of the thundercloud itself (bipolar in our case), low region between thundercloud and Earth and upper region which is connected with ionosphere. In one’s turn, up and low gaps contain ion space charge layers and it produces at least two RC chains in each of them. It is known that the ionic layer above the Earth is generated by corona discharges and the sign of this space charge is opposite to low charge of the cloud, see 2,3. The low cloud screening layer has the same sign. The capacitance and resistance of layer have been calculated on the basis of experimental data, see 3. Currents in the circuit have been calculated under the assumption of a fixed ionosphere potential and under the given charging current source in thundercell gap assuming both inductive and non-inductive charging mechanisms. The corona current has been also taken into consideration as a current source switched parallel to lower RC chain according to 4,5 It has been shown that upper layer with exponential conductivity profile can be simplified as parallel RC chain for low frequency band, < 0.1Hz. This approach is valid till 60-70 km heights, see 6,7. It allows calculating currents in development thunderstorm on the basis of simple AC circuit scheme. In the opposite case of fast transient electric fields and currents – lightning induced field change, it has been found analytically field change in all gaps in case of CG, IC and upper atmosphere discharges. The simple result is that IC lightning is always discharging the global circuit, whereas lightning in CG and upper gaps is charging it. Also the model predicts that upper atmosphere discharges may initialize CG lightning. The opposite order is assumed now for explanation of upper atmosphere ischarges activity.
Andrei E. Sorokin
Institute of Applied Physics RAS, Nizhny Novgorod, Russia
国际会议
第13届国际大气电学会议(The 13th International Conference on Atmospheric Electricity)
北京
英文
2007-08-13（万方平台首次上网日期，不代表论文的发表时间）