{"id":23200,"date":"2018-02-01T12:34:58","date_gmt":"2018-02-01T17:34:58","guid":{"rendered":"https:\/\/www.tun.com\/blog\/?p=23200"},"modified":"2022-03-16T12:12:01","modified_gmt":"2022-03-16T16:12:01","slug":"acoustic-tractor-beam-opens-door-to-levitating-humans","status":"publish","type":"post","link":"https:\/\/www.tun.com\/blog\/acoustic-tractor-beam-opens-door-to-levitating-humans\/","title":{"rendered":"Acoustic Tractor Beam Opens Door to Levitating Humans"},"content":{"rendered":"

Researchers from <\/span>the <\/span>Department of Mechanical Engineering<\/span><\/a> at the University of Bristol, UK, have <\/span>developed an acoustic tractor beam<\/span><\/a> that\u2019s so powerful that it could lead to the levitation of drug capsules or micro-surgical implements within the body and even humans. They believe it\u2019s the \u201cworld\u2019s most powerful acoustic tractor beam.\u201d <\/span><\/p>\n

The study is published in the journal <\/span>Physical Review Letters<\/span><\/a>.<\/span><\/p>\n

An acoustic tractor beam uses the power of sound to hold particles in mid-air, and can grab liquids, most solids, or small objects like insects and food.<\/span><\/p>\n

Until now, researchers thought only small objects could be levitated by acoustic tractor beams because prior attempts at trapping objects larger than the wavelength of sound failed. Those objects would spin uncontrollably when the rotating sound field transferred some of its spinning motion to the objects themselves, leading ultimately to their ejection. <\/span><\/p>\n

However, the new approach uses rapidly fluctuating acoustic vortices, which is set up in a tornado-like structure, with loud sound surrounding a silent core.<\/span><\/p>\n

\"\"
Credit: University of Bristol<\/figcaption><\/figure>\n

The researchers discovered that the rate of rotation in this structure can be manipulated by rapidly changing the twisting direction of the vortices. This allows them to then increase the size of the silent core to hold much larger objects. <\/span><\/p>\n

Using ultrasonic waves at a pitch of 40 kHz, which is similar to the pitch audible only to bats, the researchers were able to hold a two-centimetre polystyrene sphere, measuring over two acoustic wavelengths in size, in the tractor beam. This is the first time that an object this large has been trapped in a tractor beam.<\/span><\/p>\n