Researchers from the University of Kanagawa (Japan) have found a promising field of practical application of diamagnetic levitation, which is now used mainly for entertainment purposes.
For the first time, a group of scientists managed to control a levitated object without touching it and without changing the parameters of the magnetic field - watch the video.
In the experimental setup, a graphite disk 3 mm in diameter hovers over an array of neodymium-iron-boron permanent magnets. Their poles are staggered.
When the edge of the disk is irradiated with a laser, a temperature difference appears in it (about 20 degrees per second). As a result, the disk almost immediately shifts in the direction of the beam.
The height of the gap between the disk and the magnetic substrate can be adjusted both by the strength of the magnetic field and by selecting the material with the required magnetic susceptibility. By the combination of properties, pyrolytic graphite and its highly oriented form are considered the most suitable.
If you place a graphite disk on a stack of neodymium magnets, then irradiating its edge will cause rotation around its axis. For clarity, the disc is segmented like a tablet.
Based on the observed effect, the creation of new systems for converting energy (focused) light into mechanical and electrical is predicted.
By using sunlight instead of a laser, the researchers expect to achieve rotational speeds in excess of 200 rpm. Since the disc experiences virtually no friction, the energy loss should be extremely low.
Promotional video: