Speaker
Description
Lightning is highly destructive due to its high-power density and uncertain character. It is therefore important to develop better protection methods in addition to the traditional Franklin rod. Here, we present the first demonstration that laser-induced filaments can guide lightning discharges over considerable distances. In the framework of the Laser Lightning Rod project, we develop a Yb:YAG laser system for lightning control, with 500 mJ pulses of 1 ps duration at 1 kHz. The project aims at investigating its propagation in the sky, in the multiple filamentation regime and its ability to control high-voltage discharges. This pioneering experimental breakthrough has the capacity to drive advancements in the fields of both lightning protection and the comprehension of lightning physics.
During the summer of 2021, an experimental campaign was conducted on the Säntis mountain in north-eastern Switzerland with a high-repetition-rate terawatt laser. The guiding of an upward negative lightning leader over a distance of 50 m was recorded by two different high-speed cameras. With Very-High-Frequency interferometric measurements, we assess the guiding of negative lightning leaders by laser filaments. Also with X-ray scintillator device, we measure a substantial increase of the number of X-ray bursts detected during guided lightning events. Characterizing the lightning events with and without laser filaments, over the wide electromagnetic spectrum, we are able to corroborate the guiding of 50m long atmospheric discharges with a laser.
Although this research field has been very active for more than 20 years, this is the first field-result that experimentally demonstrates lightning guided by lasers. This research opens the way for novel atmospheric uses of ultrashort lasers, marking a significant improvement in advancing laser-based lightning protection systems, designed for critical sites and expansive infrastructures. Nonetheless, we demonstrated the possibility to pierce holes into clouds by the help of laser filaments. This could become useful for optical ground to satellite communication, which is orders of magnitude faster than radio communication, but can only be done at clear sky.
