Physicists in Spain have calculated that substantial amounts of energy could be transmitted through air by using special materials to shape the magnetic fields around conductors. Although the concept has yet to be verified in the lab, the researchers say that it could lead to a viable method of transmitting electrical power, as well as applications in magnetic sensors and studies of the brain.
They have used the theory of transformation optics to propose a new way of concentrating and transmitting electrical energy.
This computer visualization shows the distribution of magnetic energy between two magnets held in separate metamaterial shells. (Courtesy: Alvar Sanchez and colleagues)
The team created a computer model of a transmitter-receiver system with a magnetic field source at the centre of a shell. The shell is made from a metamaterial with a magnetic energy density that would always be zero. In the case of power transmission, the magnetic field source would be a current-carrying coil.
The presence of the shell causes all the energy contained in the inner field to be delivered to the outer edge of the shell. Therefore the magnetic field radiated around the magnet into space is much stronger than if the shell had been a normal magnet or free space. If a second metamaterial shell were placed close by, the magnetic field of the first shell would then induce a magnetic response on the surface of the second shell. In this case, the effect of the shell is to transfer magnetic energy from outside of the shell to the centre of the shell without any loss.
Beyond energy transmission, the researchers suggest the ability of the shell to concentrate magnetic fields into a small space could enhance the accuracy of magnetic sensors. This could extend the reach of a medical research technique called transcranial magnetic stimulation, in which parts of the brain can be temporarily activated or deactivated by magnetic fields.
SOURCe – Physics World