Metamaterial for enhancing magnetic fields

Professor at Duke University (Durham, North Carolina, USA) Yaroslav Urzhumov proposed a method for amplifying the magnetic component of electromagnetic waves without increasing their electrical component. The fact is that biological tissues for magnetic fields are transparent, and it would be useful to learn how to strengthen the magnetic component of electromagnetic waves.

This would open the way to the creation of safe levitating trains, to the construction of new wireless energy transmission systems, and to the solution of a number of other problems where there is a need for strong alternating magnetic fields, and at the same time it should be safe for humans. New systems will be more economical and safer than existing analogues.

To obtain the desired result, Yaroslav Urzhumov proposed the use of magnetically active metamaterial, due to which it is possible to obtain sufficiently strong magnetic fields using a relatively low current. Such a solution would reduce electric fields, which are parasitic in this case, and create safe and powerful electromagnetic systems.

Numerical modeling conducted by Yaroslav and his colleagues showed that macroscopic objects created on the basis of metamaterials with negative magnetic permeability are capable of amplifying magnetic forces in low-frequency fields under a number of conditions. Researchers called this phenomenon a magnetostatic surface resonance, which is similar in principle to plasmon surface resonance occurring in optics, which manifests itself in materials with negative dielectric constant.

The metamaterial modeled by scientists, characterized by a very high, special anisotropy, has a negative magnetic permeability in one direction, and in all other directions the magnetic permeability is positive. Judging by the calculations, the manufactured objects will be able to sharply increase the magnetic field precisely due to resonance.

The application of this phenomenon in magnetic levitation systems will increase the mass of lifted objects many times over, and the cost of electricity, in comparison with traditional counterparts, will not increase. The author of the development, a former student of the Moscow Physics and Technology Institute, Yaroslav Urzhumov is sure of success.

New systems of unusual control of magnetic forces in electromagnetic fields can work in other areas, such as tiny optical tweezers for holding atoms, or the latest electromagnetic weapons. This may also include WiTricity Technology Systemsserving for wireless energy transfer through a strong pulsating magnetic field, which are completely harmless to both humans and animals.

In accordance with the models of Yaroslav, a group of experimenters at Boston College (Boston, Massachusetts, USA) creates a prototype of such a metamaterial, one might say, a magnetic amplifier.

As for wireless transmission through magnetic fields, recently, together with the Toyota Institute, a group of Yaroslav Urzhumov demonstrated a very practical transmission of electricity over a distance through low-frequency magnetic fields.

To improve the transmission efficiency, scientists built a square superlens that was placed between the transmitter and receiver. The square lens consisted of many cubes covered with spiral conductors. The resulting structures with the property of metamaterial interacting with magnetic fields transferred energy in a narrow cone with maximum intensity.

A coil — a transmitter — was placed on one side of the superlens, along which an alternating current was passed, creating an alternating magnetic field. This magnetic field, as expected, decreased its intensity in proportion to the square of the distance from the transmitter, however, thanks to the superlens, the transmitter, located on the other side of it, received a sufficient amount of energy even at a distance of 30 cm. Without the use of an intermediate lens, the transmission distance did not exceed 7 6 cm

The scientist said that such a wireless transmission using metamaterials was already carried out in the laboratory of Mitsubishi Electric, but only at a distance not exceeding the size of the transmitter. Now, using precisely magnetic fields, high safety and efficiency are achieved. Magnetic fields are not strongly absorbed by most materials; moreover, magnetic fields by induction up to 3 T are safe, and are already used in tomography.

In the future, on this basis, the creation of wireless mini gadgets for electronic gadgets. Super lenses will focus magnetic fields to charge a particular device, and the lens parameters will be able to change, and the focus will move in space, for example, following the smartphone that its owner carries around the room, constantly changing location.

See also on the topic:

History of discovery and nature of magnetism

Magnetic levitation. What is it and how is it possible?

Faraday cage. Work and application

Wireless Power Transmission - Basic Methods