Guiding Electricity Through the Air Using Ultrasound Pulses

Electricity is naturally unpredictable, typically requiring wires and circuits for control. However, researchers in Europe and Canada have successfully directed sparks through open air and around obstacles using ultrasound waves.

In open air, electricity naturally spreads in unpredictable directions—much like a lightning bolt. Its path is influenced by slight variations in air density, charge distribution, and attraction to metal objects. Managing these factors makes precise control challenging.

Precision Control of Electric Sparks Through Air

In a recent study, researchers from the University of Helsinki, Public University of Navarre, and the University of Waterloo developed a technique to steer electric sparks through the air. This method enables sparks to be guided with such precision that they can curve around obstacles and strike targeted points on a material, even if it isn’t conductive.

“We first noticed this phenomenon over a year ago, but it took months to control and even longer to understand,” said Asier Marzo, the study’s lead researcher.

The key to this technique is ultrasound. Sound waves at these frequencies generate air pressure strong enough to levitate lightweight objects. While they don’t directly push the electricity, they effectively shape its path.

When a spark forms, it heats the surrounding air, causing it to expand and lower in density. Since electricity naturally favors traveling through lower-density air, the spark moves in that direction. Ultrasound pulses manipulate this warm, less dense air, allowing the spark’s movement to be guided with remarkable precision.

Ultrasound Emitters Guide Sparks with Precision

To test the method, the team used two circular arrays of ultrasound emitters positioned around a Tesla coil’s spark point. When activated, the plasma spark shifted from a chaotic, branching pattern into a single controlled line. By tilting the emitter ring or adjusting the intensity of individual emitters, researchers could steer the spark in specific directions.

This technique enabled the team to direct plasma toward certain electrodes while avoiding others, potentially enabling controlled switching in wireless circuits. It also allowed sparks to strike materials that electricity wouldn’t typically reach. Possible applications include etching patterns into bacterial colonies and creating haptic feedback devices that deliver low-power plasma sensations to the skin.

“I’m excited about the potential of using faint sparks to create controlled tactile sensations in the hand, possibly leading to the first contactless Braille system,” said Josu Irisarri, the study’s first author.

The research was published in Science Advances.

Read the original article on: New Atlas

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