Lightning dart¹ across the sky in a flash. And even though we can use lightning rods to increase the probability of it striking at a specific location, its exact path remains² unpredictable. At a smaller scale, discharges between two electrodes behave in the same manner, streaking³ through space to create electric arcs where only the start and end points are fixed⁴. How then can we control the current so that it follows a predetermined path? Professor Roberto Morandotti and his colleagues have discovered a way to guide electric discharges--and even steer⁵ them around obstacles--through the clever use of lasers. This scientific breakthrough was published on June 19, 2015, in Science Advances, the new open-access journal from the prestigious⁶ editors of the international journal Science. Using the Advanced Laser Light Source (ALLS) facility, researchers from the INRS Énergie Matériaux Télécommunications research centre tackled this challenge, which had previously⁷ been the subject of intensive research, particularly in the 1970s. 

 

Electric arcs have long been used in such technologies as combustion⁸ engines, pollution control applications, lighting⁹, machining and micromachining. Potential applications could multiply with the ability to precisely¹⁰ control the path they take. A first step in this direction has been made and research into the new possibilities and parameters¹¹ for guiding electric arcs promises to spark researchers' creativity.

 

Recent scientific and technical advances, as well as the ingenuity¹² of Professor Morandotti's team (particularly researcher Matteo Clerici, a postdoctoral fellow with the research group at the time of the experiments), set the stage for this spectacular demonstration¹³, where we see an electric charge follow a smooth path along a straight or parabolic trajectory¹⁴.

 

Experimental figures show how different shaped lasers give discharges distinct properties and trajectories¹⁵. By combining beams, it is even possible to achieve an S-shaped trajectory, with all other kinds of trajectory achievable in principle.

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