Amazing stuff! This news got Benjamin Franklin's attention!
"Though scientists have long understood how lightning strikes, the precise atmospheric events that trigger it within thunderclouds remained a perplexing mystery. ... has revealed the powerful chain reaction that triggers lightning. ...
how they determined strong electric fields in thunderclouds accelerate electrons that crash into molecules like nitrogen and oxygen, producing X-rays and initiating a deluge of additional electrons and high-energy photons — the perfect storm from which lightning bolts are born.
“Our findings provide the first precise, quantitative explanation for how lightning initiates in nature," ... "It connects the dots between X-rays, electric fields and the physics of electron avalanches." ...
“By simulating conditions with our model that replicated the conditions observed in the field, we offered a complete explanation for the X-rays and radio emissions that are present within thunderclouds,” ...
Published ... in 2023, the model, Photoelectric Feedback Discharge, simulates physical conditions in which a lightning bolt is likely to originate. The equations used to create the model are available in the paper for other researchers to use in their own work. ..."
From the key points and abstract:
"Key Points
- Photoelectric feedback discharges initiate lightning with no constrains on densities or physical origin of seed runaway electrons
- Photoelectric feedback discharges are a unified mechanism for production of initial breakdown pulses (IBPs), narrow bipolar events (NBEs), energetic in cloud pulses (EIPs), and terrestrial gamma ray flashes (TGFs)
- Similarity laws explain observed variability of IBPs, NBEs, EIPs, and TGFs produced at different altitudes in the Earth's atmosphere
Abstract
Terrestrial gamma ray flashes (TGFs) are high-energy photon bursts that have been linked to short bursts of electromagnetic radiation associated with lightning activity. The most puzzling unexplained aspect of these events is that gamma rays originate from very compact regions of space while the source regions often seem to be optically dim and radio silent when compared to processes in ordinary lightning discharges.
In this work, we report a mechanism that allows precise quantitative explanation of these peculiar features of TGFs and their relationships to the observed waveform characteristics of associated radio emissions.
The mechanism represents an extension of earlier ideas on feedback processes in growth of relativistic runaway electron avalanches ... and is based on a recent demonstration of the dominant role of the photoelectric feedback on compact spatial scales ... Since discussed events often occur in isolation or precede formation of lightning discharges, the reported findings propose a straightforward solution for the long-standing problem of lightning initiation."
A bolt is born! Atmospheric events underpinning lightning strikes explained (original news release)
Credits: The Flyover
Figure 8
Conceptual representation of conditions required for transition from fast positive breakdown (FPB) to fast negative breakdown (FNB) based on relationship between the relativistic feedback threshold and the minimum negative streamer propagation fields.
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