It may sound like something straight out of a sci-fi movie, but real-life scientists have been busy working on a super-precise laser tractor beam system to change the path and direction of lightning.
There's a very practical reason behind it too: lightning strikes are the main natural cause of bushfires in Australia, and a growing number of wildfires in the US, so a lightning diversion system has the potential to save lives, keep wildlife safe, and protect huge stretches of vital ecosystems.
"We can imagine a future where this technology may induce electrical discharge from passing lightning, helping to guide it to safe targets and reduce the risk of catastrophic fires," says physicist Vladlen Shvedov from Australian National University.
The system makes use of a laser beam that mirrors the same process lightning uses, creating a path and a specific target for an electrical discharge.
Put simply, lightning is just an electric current bridging the gap between a positively charged point on the ground, and a negatively charged point at the base of a thundercloud (created by the intense activity of frozen raindrops).
The laser beam proposed by the researchers sets a spot for such an electrical discharge to be released; in their experiments, they used graphene microparticles as the mediator of the charge.
"Here, we propose and demonstrate an efficient approach for triggering, trapping and guiding electrical discharges in air. It is based on the use of a low-power continuous-wave vortex beam that traps and transports light-absorbing particles in mid-air," the team writes in the study.
Of course, the researchers haven't tested such a laser-induced air heating system with actual lightning out in the wild yet, but the smaller scale results obtained in the lab suggest that electrical discharges such as lightning can be exactly controlled.
"The experiment simulated similar atmospheric conditions to those found in real lightning," says Shvedov.
The technology works over long distances, and only requires a low-power laser, which makes the system affordable, precise, and easy to put together. The laser intensity used here is around a thousand times less than in previous research.
While the term tractor beam actually originates in science fiction – and has since been adapted by shows such as Star Trek – the laser system developed here fits the description. It's moving lightning rather than the USS Enterprise, but the same principle applies.
Beyond lightning, the same careful control of electrical discharge shown here could also be used in manufacturing and in medicine – to carefully remove cancerous tissue without invasive surgery, for example.
"We have an invisible thread, a pen with which we can write light and control the electrical discharge to within about one tenth the width of a human hair," says physicist Andrey Miroshnichenko, from the University of New South Wales, Canberra.
"We are really at the start of learning what this completely new technology might mean."
The research has been published in Nature Communications.