“Lightning strikes twice” is not just a beautiful phrase, but a scientific fact. Electrical discharges during a thunderstorm often follow the same path, and until recently, scientists did not understand why this is so.
An international team of scientists has tried to figure out why this is happening. Physicists have studied lightning discharges with a LOFAR (Low-Frequency Array) telescope. This method allowed them to obtain nanosecond lightning images.
“These data allowed us to study lightning in such detail that we were able to get to the primary processes that underlie this phenomenon,” says physicist Brian Hare of the University of Groningen. “The use of radio waves allowed us to look into the depths of thunderclouds.”
The formation of lightning begins with the appearance of a plasma pocket – a small ball of heated and ionized gas. From it streams diverge charges, forming a kind of network of channels. Thanks to LOFAR, scientists have seen that not all charge passes through these channels. Part of the charged particles seeps through the gaps in the discharge channels, and forms the so-called needles.
These very needles exist for a very short time. Other lightning researchers could not see them. And it is precisely these structures that lead to the fact that lightning strikes twice at the same point — the needles serve as a kind of guide for new discharge channels.