Electricity is extremely dangerous, but also extremely useful when we can contain it and send it from A to B. It turns out that we do not need wires, tubes with special gases, or lasers to do that – even sound can be used to manipulate electric charges to behave how we wish, new research has revealed.

Researchers looked at electric sparks, chaotic releases of plasma that have a variety of utilities in technology. You might have seen similar releases of plasma in Tesla coils or plasma balls. In general, these sparks are very chaotic and are used in places where that chaos is manageable or not too damaging. Think of killing bacteria, welding, high-voltage electronics, producing tactile sensations, and even igniting the fuel of some car engines.

Having more control over this plasma can improve those applications – and even open the door for more. Researchers have worked out how ultrasound can be used to control these sparks in incredible ways. They can be made to move around obstacles and hit specific spots on a target, even when the material is not an electrical conductor.

“We observed this phenomenon more than one year ago, then it took us months to control it, and even longer to find an explanation,” the study’s lead researcher Dr Asier Marzo, from the Public University of Navarre, said in a statement.

Seeing the process in action is almost magical, but it works by using the effects the plasma has on the air against itself. The spark warms up the air, lowering its density as it expands. The ultrasonic waves are used to shape this hot, less dense air. The sparks then naturally follow those regions because it has a lower breakdown voltage.

Another current method to move the sparks in the right direction is to use laser flashes with precise timing to create an electrical discharge in the air. Such an approach wouldn’t be able to work on delicate material or living organisms.

“Precise control of sparks allows their utilization in a wide variety of applications, such as atmospheric sciences, biological procedures and selective powering of circuits,” said co-author Professor Ari Salmi from the University of Helsinki.

“I am excited about the possibility of using very faint sparks for creating controlled tactile stimuli in the hand, perhaps creating the first contactless Braille system,” added the study’s first author Josu Irisarri from the Public University of Navarre.

The study is published in the journal Science Advances.