Penn State University researchers have successfully simulated the conditions inside thunderstorm clouds that initiate lightning strikes inside a block of plastic roughly the size of a deck of cards.
The research team behind the successful simulations said their work is the first to demonstrate the ability to create such small lightning strikes in a laboratory setting, offering researchers an unprecedented opportunity to study one of Earth’s most enigmatic phenomena up close and at a lower cost than in atmospheric studies.
The Penn State team also suggests that their lighting in a block demonstration could help improve existing technologies, including more compact and potentially safer X-ray sources in local doctor offices and security checkpoints.
“For us to realize that these voltages and electric fields, generated inside of these materials that are theoretically the same as in thunder clouds, was a real breakthrough,” explained Victor Pasko, professor of electrical engineering at Penn State and lead author on a paper describing the discovery.
Modeling How Lightning Strikes Form Motivated New Experiments
In nature, lightning strikes occur when mismatched charges clash in Earth’s atmosphere. Within a storm cloud, electrons move freely through an electrical field before colliding with oxygen and nitrogen atoms. These collisions result in bright bursts of electromagnetic energy called gamma ray flashes. Terrestrial gamma ray flashes that originate on Earth are often so powerful that they can send beams of radiation hundreds of miles into space.
According to a statement from the Penn State research team announcing the discovery, these gamma ray flashes can form an electron ‘avalanche’ similar to a snow avalanche, only instead of accumulating ice, electron avalanches accumulate energy. Under the right conditions, this relativistic runaway electron avalanche can trigger a lightning strike.
While a typical thunderstorm can produce electric potentials of around 100 million volts, that energy is spread across kilometer-scale cloud regions. However, previous studies have indicated that a similar electron avalanche leading to lightning strikes can occur in much denser materials and at much smaller scales.
Models Confirm Creation of Runaway Photoelectric Feedback Loop on Smaller Scale
Instead of creating potentially dangerous high-energy conditions in a lab, Pako and colleagues decided to model the phenomenon in high-density materials. In theory, these models would produce the same runaway photoelectric feedback loop that causes lightning strikes, but on a scale of a few centimeters rather than across kilometers.
“Theoretically, you can reproduce this large-scale phenomenon that we see in lightning in a very small volume,” Pasko explained.
When selecting the material for their lighting strike models, Pasko said it primarily needed to be “a kind of insulating material.” The team ultimately settled on models using acrylic, quartz, and bismuth germanate as the base materials. According to the team’s statement, bismuth germanate is “a hard crystal commonly used for X-ray detection in labs and supporting experiments in space,” and is also 1,000 times denser than air.
After selecting their base materials, the team modeled an external energy source that bombarded the materials with electrons. According to Pasko, the team used the “exact models” used in lightning research, only scaled down. As hoped, these simulations, supported by previous experiments suggesting a similar phenomenon in dense dielectric materials, resulted in electron avalanches triggering simulated lighting strikes at the centimeter scale.
“We calculated that when supplied with a high-powered electron source, lightning can be triggered in everyday insulating materials like glass, acrylic, and quartz,” Pasko explained. “We were amazed because we were able to model the same phenomena in a material one thousand times denser than air, and strike a thousand times faster than in thunder clouds – one-billionth of a second.”
Controlling Electron Avalanches Could Improve Medical X-Rays and Airport Scanners
When discussing the study’s implications, the Penn State team noted that being able to produce lightning strikes in a lab setting on a manageable scale “opens new pathways for studying lightning physics under controlled conditions,” including helping researchers investigate how lightning is triggered and propagates without the high costs of aerial balloons, drones, or aircraft-based studies.
“If you’re able to experiment with lightning-like conditions on a desktop under controlled conditions, it would be wonderful — much more cost-effective and could answer so many questions,” Pasko explained.
Although the research team’s models open up opportunities for studying lighting and related properties, they also noted that creating and managing electron avalanches in dense dielectric materials could have practical applications. Among the technologies highlighted by the team were potential advancements in potentially safer, more compact X-ray sources for medical imaging applications and advanced scanning technologies at airport security checkpoints.
The study “Relativistic Feedback Discharges in Dielectric Solids” was published in Physical Review Letters.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.