The lightning in the sky, that is sometimes followed by the sound of thunder; travelling down all the way from the high heavens is one of the few mysteries to be unravelled even today! Lightning is, undoubtedly, one of the most destructive forces in Nature. However, we know surprisingly very little about the basic causes and the working of this powerful phenomenon, including the simple fact of how the electrical current that flows through a lightning flash is correlated to the temperature of the lightning strike! Scientists, currently researching on the lightning phenomena understand only the basic physics of lightning but as to how it is initiated and travels through space and then down to the ground are not fully known in details!
It is estimated that lightning causes more than US dollar five billion in damages every year in the USA and the fatalities from lightning strike are more in numbers than hurricanes that sometimes strike the USA! A direct hit by a lightning strike can melt a power cable! It can even start a forest fire, which is correlated to the heat generated by a lightning strike! In China where specialized research on 'lightning phenomena' is being carried out, they have found out a mathematical co-relation between the intensity of the lightning current and the temperature inside the core of the lightning! It is estimated that around 100,000 lightning strikes our Earth every single day! However, the randomness of the occurrences makes it difficult for scientists to study these phenomena in a systematic or effective manner.
One way to study this phenomenon in a laboratory is by using an impulse generator system that can create artificial lightning with currents of tens of thousands amperes! In comparison, a household or automotive fuse is rated well below a hundred amperes! In contrast, a natural lightning strike will reach current levels of between 10,000 to 1,000,000 amperes! The Chinese research team has been able to record these temperatures within a millisecond of natural lightning strike, by measuring the intensity of the light on various wavelengths!
After many studies at the same location, over and over again; they concluded that the correlation between current measured and lightning temperature is similar, despite very large variance in the momentary strike-generated current! The way ahead, is to follow up and compare these measurements, with temperature measurements of rocket-fired artificial lightning with that from natural lightning! It is hoped that with better understanding of the 'physics' of 'lightning'; scientists can go forward to better deal with lightning matters that are a potential threat to any power transmission system; and have better and more 'foolproof' way of protecting high tension electric power transmission grids across the world!
Engr.S.A.Mansoor
