PALAISEAU, France – With the help of a laser-based lightning rod, laboratory-generated lightning was coaxed to strike the same place not just twice but numerous times, and contrary to the path of least resistance. This advance demonstrates the potential of such rods for research and protection.
In earlier experiments, femtosecond lasers were used to produce a virtual lightning rod from ultrashort filaments of ionized gas that act as electrical guide wires. Now, for the first time, researchers in France have used laser-induced atmospheric filaments to reroute an electrical discharge from striking the “highest tree,” instead striking a lower object – over and over again.
Integrated picture of the discharge and measurements of the voltage and current in the case of an unguided discharge (a, b) and a laser-guided discharge (c, d). Courtesy of AIP Advances, American Institute of Physics.
A team from Laboratoire d’Optique Appliquée, EADS France, CILAS and Astrium conducted experiments to test how well lasers can harness and control lightning. They sent a laser beam past a spherical electrode toward an oppositely charged planar electrode. The laser stripped away the outer electrons from the atoms along its path, creating a plasma filament that channeled an electrical discharge from the planar electrode to the spherical one.
A longer, pointed electrode was added to determine whether the filament could redirect an electrical discharge from its normal path.
They found that they could divert the electrical discharge even after it was already on its way, meaning that they could change the path of the lightning.
“The laser lightning rod would be a valuable alternative to lightning rockets,” devices that control lightning strikes, said Dr. Aurélien Houard of the Laboratoire d’Optique Appliquée.
The research was published online in the American Institute of Physics’ journal AIP Advances