Lightning sparks the discovery of a new electromagnetic wave

In the realm of electromagnetic waves, new discoveries often stir the academic world. But when lightning leads to the identification of an entirely new type of wave that challenges current understanding, it generates ripples beyond academia.

This is precisely the case with a recent investigation by two scientists from the University of Alaska Fairbanks (UAF).

The breakthrough research has led to the discovery of a new type of electromagnetic wave, referred to as a “specularly reflected whistler.”

The role of lightning energy

The remarkable discovery was made by Vikas Sonwalkar, a highly respected professor emeritus, and Amani Reddy, a dynamic assistant professor at UAF.

The researchers identified this new wave, which intriguingly carries lightning energy from the ionosphere at low latitudes all the way to the magnetosphere, a critical region of space surrounding Earth.

Previously, it was believed that lightning energy entering the ionosphere at low latitudes remained trapped within this atmospheric layer and did not reach the radiation belts – those crucial zones of charged particles encircling our planet.

However, the current study completely turns that long-held assumption on its head, revealing a much more complex interaction between lightning energy and Earth’s magnetic environment.

“We as a society are dependent on space technology. Modern communication and navigation systems, satellites, and spacecraft with astronauts aboard encounter harmful energetic particles of the radiation belts, which can damage electronics and cause cancer,” said Sonwalkar.

“Having a better understanding of radiation belts and the variety of electromagnetic waves, including those originating in terrestrial lightning, that impact them is vital for human operations in space.”

Discovery of the electromagnetic wave

The newly discovered wave, which Sonwalkar and Reddy have termed a “specularly reflected whistler,” carries lightning energy that is reflected upward by the ionosphere’s lower boundary in the opposite hemisphere.

Whistler waves, including this new type, produce a distinctive whistling sound when played through a speaker.

This type of wave contrasts with the magnetospherically reflected whistler, which is generated when lightning energy enters the ionosphere at higher latitudes and undergoes one or more reflections within the magnetosphere.

The power of lightning in Earth’s atmosphere

Lightning is not just a spectacular natural phenomenon; it plays a crucial role in Earth’s atmospheric processes and space environment.

Each lightning strike releases a tremendous amount of energy, not only illuminating the sky but also impacting the ionosphere and magnetosphere.

This energy can travel vast distances, influencing the behavior of charged particles in the upper atmosphere and beyond.

The discovery of the specularly reflected whistler wave further underscores the significance of lightning as a driver of electromagnetic activity, revealing new ways in which this powerful force of nature interacts with Earth’s magnetic field and space weather.

Implications of the new electromagnetic wave

The researchers used historical plasma wave data from NASA’s Van Allen Probes and lightning data from the World Wide Lightning Detection Network to support their findings.

They developed a wave propagation model that, when accounting for specularly reflected whistlers, showed a doubling of lightning energy reaching the magnetosphere.

“This implies that specularly reflected whistlers probably carry a greater part of lightning energy to the magnetosphere relative to that carried by magnetospherically reflected whistlers,” Sonwalkar explained.

Given that the majority of lightning occurs in tropical and subtropical regions, this discovery has significant implications for understanding the dynamics of Earth’s magnetosphere.

Role of whistler waves in Earth’s magnetosphere

The research conducted by Sonwalkar and Reddy highlights the coexistence of specularly reflected whistlers and magnetospherically reflected whistlers in the magnetosphere, reshaping our understanding of how lightning energy interacts with Earth’s magnetic environment.

The study continues a line of inquiry into the impact of lightning-generated whistler waves on radiation belt physics, a field that has been studied since the 1950s.

Sonwalkar and Reddy are affiliated with the Department of Electrical and Computer Engineering in the UAF College of Engineering and Mines, with Reddy also linked to the UAF Geophysical Institute.

The research was supported by grants from the National Science Foundation and NASA EPSCoR.

The study is published in the journal Science Advances.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–