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Researchers defy 19th-century law of physics in 21st century boost for energy efficiency
Research led by a University of Sussex scientist has turned a 156-year-old law of physics on its head in a development which could lead to more efficient recharging of batteries in cars and mobile phones.
Dr Jordi Prat-Camps, a research fellow at the University of Sussex, has for the first time demonstrated that the coupling between two magnetic elements can be made extremely asymmetrical. Working with colleagues from the Austrian Academy of Sciences and University of Innsbruck, Dr Prat-Camps' research rips up the physics rule book by showing it is possible to make one magnet connect to another without the connection happening in the opposite direction.
The findings run contrary to long-established beliefs of magnetic coupling, which emerge from the four Maxwell equations dating back to the seminal works of Michael Faraday and James Clerk Maxwell in the 19th century.
Dr Prat-Camps said: "We have created the first device that behaves like a diode for magnetic fields. Electric diodes are so crucial that none of the existing electronic technologies such as microchips, computers or mobile phones would be possible without them. If our result for magnetic fields would have one millionth of the same impact as the developments in electric diodes, it would be a hugely impactful success. The creation of such a diode opens up a lot of new possibilities for other scientists and technicians to explore. Thanks to our discovery we think it might be possible to improve and the performance of wireless power transfer technologies to improve the efficiency of recharging phones, laptops and even cars."
Circumventing Magnetostatic Reciprocity: A Diode for Magnetic Fields (DOI: 10.1103/PhysRevLett.121.213903) (DX)
(Score: 3, Interesting) by ElizabethGreene on Saturday November 24 2018, @05:40PM
My library was closed yesterday and I could not get in to read the paper. The following is based entirely on third party reporting, abstract, and the pictures attached to the paper.
I think I understand it. There is a conductive ring made of U shaped channel. Inside that ring are two coils. The ring rotates at a constant rate and the coils remain fixed such that the ring is continuously rotating past them.
If you apply a current to one coil, it creates a magnetic field. That induces a current in the ring like a magnet falling through a copper tube. As that induced current decays, it sheds a magnetic field. If the rotation of the ring carries that decaying magnetic field toward the second coil then that induces a current in the second coil. If the rotation of the ring carries the decaying magnetic field away from the second coil then the current dissipates as heat.
Magic: The magnetic field can move from Leading coil to Trailing, but not trailing to leading. It's a clever bit of kit. Somebody is going to try (and fail) to make a perpetual motion machine out of it, but it will be fun to watch them try. (Protip: The energy put into rotating that ring isn't free.)