In the early days of scientific exploration, researchers observed natural phenomena and began to unravel the mysteries behind how lightning forms.
These brief yet incredibly bright bursts of radiation, referred to as Terrestrial Gamma Ray Flashes (TGF), were identified by a research team at Osaka University in Japan during a lightning event.
Interestingly, TGFs are typically observed in space, associated with supernovae and black hole jets. This raises the question: how does lightning produce the energy required to generate them?
Recent papers published in the journal Advances in Science potentially provide answers. While scientists previously believed that TGFs were caused by the rapid acceleration of electrons, testing this theory has proven challenging. The radiation often occurs in the final microsecond and is concealed by cloud cover.
This is why researchers involved in the new study employed innovative techniques to observe thunderstorms, utilizing a multi-sensor system that includes optical, radio frequency, and high-energy radiation sensors.
“The multi-sensor observations conducted here are unprecedented,” stated Dr. Harufumi Tsuchiya, the senior author of the paper. “While some mysteries persist, this approach has significantly deepened our understanding of these intriguing radiation burst mechanisms.”
So, what did they find? Collectively, the sensors unveiled two channels of charged particles known as the discharge pathway—one descending from the thundercloud to the TV tower, and the other ascending from the tower.
The scientists observed the formation of TGFs occurring 31 microseconds before the two pathways converged, resulting in a highly concentrated electric field where electrons accelerated at nearly the speed of light.
Once the two pathways merged, the burst continued for an additional 20 microseconds, yielding a lightning strike of -56 kiloamperes. (Don’t let the negative sign confuse you—it merely indicates the direction from cloud to ground. This current is exceptionally high, typical of lightning.)
Wada Yutaka, the lead author of the study, remarked, “The opportunity to examine extreme processes such as TGFs stemming from lightning enhances our understanding of the high-energy dynamics present in Earth’s atmosphere.”
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Source: www.sciencefocus.com
