How are thunderstorm lightning created? A Catalan scientist is about to find out.
Gustau Catalán, a researcher at the Catalan Institute of Nanoscience and Nanotechnology, has promoted the research in collaboration with Xi'an Jiaotong University and Stony Brook University.
BarcelonaSome suggest that thanks to small fires caused by lightning, humans were able to begin to use and master fire. This was crucial for the species to achieve higher survival rates, induce a change in diet, and favor technical development. But despite the importance of this phenomenon and the million years of progress of the species, scientists still have not been able to explain what causes high-intensity electrical discharges to fall from the sky.
Now, everything indicates that this mystery may have been solved. Five years ago, ICREA professor and leader of the Oxide Nanophysics group at the Catalan Institute of Nanoscience and Nanotechnology (ICN2), Gustau Catalán, and Xin Wen, who was then a doctoral student at Xi'an Jiaotong University (China), set out to demonstrate that ice is a material. That is, it is capable of generating electricity when its structure is bent irregularly. For Catalán, demonstrating this property of ice was "almost trivial." Together with Wen and the collaboration of Stony Brook University (New York), they managed to demonstrate this in the first year of the research, in 2021.
From ice particle to lightning
But the tricky part came next. The fact that ice is a felchoelectric material opened up a wide range of hypotheses that made this search "truly exciting," since, among other things, it could help explain why large electrical discharges are generated kilometers high. "Formulating a hypothesis like this is completely unusual; you have to be very cautious when making assumptions, and when that striking search fell through, I felt a little uneasy—it's still very big!" emphasizes the leader of the ICN2 Oxide Nanophysics group.
Until now, it was known that lightning was generated by two ice particles colliding in the clouds, but it was not understood how these pieces of ice could be charged with electricity, since the latest scientific searches had ruled out the possibility that ice could be charged.
Catalán and Wen's work was to dare to demonstrate that ice particles are charged by deformation and not by compression, as had already been discarded. "When analyzing the electrical charge generated by the ice block deformed by two metal sheets, the results coincided with the values observed in previous experiments on ice particle collisions in storms," says the ICREA professor.
Justifying the results and convincing journals that their interpretation of the origin of lightning was correct was what took them the longest. "It's natural; they wanted to check that we weren't talking nonsense," Catalán ironically emphasizes. Finally, the research, defense, and justification of the years of work have earned them the publication of the academic article in the journal Nature Physics.
The technological implications derived
Having the ability to electrically charge a material as common as ice opens the door to a host of technological and scientific advances previously unimaginable. "I feel like we've only just scratched the surface," the professor explains. In fact, Catalán noted that the layer of water in contact with the surface behaves like a solid, that is, like ice, which could mean that the properties of flexoelectricity could also be applied in a similar way to water. "This property could have an impact in different areas: it could be applied both in the ocean and in people, since we are composed of 70% water."
With the anticipation of having initiated a major discovery, the team has already registered a patent: the use of flexoelectricity as an energy source or as a seismic movement sensor. "Today, we don't consider the electric charge generated by ice deformation to replace renewable energy sources because the effort required to bend the ice is greater than the electric charge obtained, but it is true that we have seen that our research can help increase the efficiency of current photovoltaic panels," asserts the Catalan.
The study's author also emphasized that this discovery would not have been possible without international cooperation, "specifically between the European Union, the United States, and China," and lamented the consequences of Trump's policies on the scientific community.