From the series of articles "What Is Going On Up There?".
In this chapter, we can only talk about aircrafts, because jets cannot get to the ground structures. Reader can predict the author’s point of view without further reading. If we identify a jet with the upward lightning, penetrated above thunderstorm cloudiness, then the danger of its impact should be considered far-fetched. The results of detailed studies of field upward discharges from high-rise ground structures and trigger lightning during rocket sounding serve as the basis for this. Such discharges do not have the main stage, during which their channels could rapidly lose the charge (in 1 – 10 μs), thus exciting a current wave with an amplitude of tens to hundreds kiloamperes. As for the current in the process of forming the upward leader, its magnitude is approximately 3 ranks less than that indicated above.
Current in the channel of a real blue jet can only be estimated by the indirect method, registering its electromagnetic low-frequency radiation in the far away area. Usually, the obtained current values do not exceed 100 A. Therefore, it is needless to talk about the danger of contact between the jet channel and the aircraft. By analogy with the upward lightning, the reader can recall the repeated components, which, using the already formed channel, propagate from the cloud to the ground, ultimately forming the main stage, with a sufficiently large pulse current. Fortunately, nothing similar was observed in jets.
6. Conclusion
Very little can be concluded, in case of interest in high-altitude discharges in applied terms, paying attention only to their danger to modern technical objects. Is it beautiful? – Yes, definitely!
E. M. Bazelyan, Dr. Sc. (Eng.), Professor
Krzhizhanovsky Energy Institute, Moscow
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