Metamaterial anisotropic flux concentrators and magnetic arrays

Abstract

A metamaterial magnetic flux concentrator is investigated in detail in combination with a Halbach cylinder of infinite length. A general analytical solution to the field is determined and the magnetic figure of merit is determined for a Halbach cylinder with a flux concentrator. It is shown that an ideal flux concentrator will not change the figure of merit of a given magnet design, while the non-ideal will always lower it. The geometric parameters producing maximum figure of merit, i.e., the most efficient devices, are determined. The force and torque between two concentric Halbach cylinders with flux concentrators is determined and the maximum torque is found. Finally, the effect of non-ideal flux concentrators and the practical use of flux concentrators, as well as demagnetization issues, is discussed. V C 2013 AIP Publishing LLC. [http://dx

Experimental realization of magnetic energy concentration and transmission at a distance by metamaterials

“…21,22 Other studies have proposed to concentrate static magnetic fields using related ideas with other geometries, 23 and also in arrangements involving magnets. 24 In this work, we develop and construct actual metamaterial shells to experimentally confirm the properties of magnetic concentration, expulsion, and concentration at a distance. We do not only validate the theoretical ideas of Ref.…”

The magnetic properties of the hollow cylindrical ideal remanence magnet

“…By combining the ideal remanence magnet with a flux concentrating device, which is able to concentrate the field lines in a cylinder bore (18; 19), the field generated by the ideal remanence magnet can be enhanced as desired. The flux concentrating device cannot change the efficiency of a given magnet design (20), but will enhance the field generated by the permanent magnetic structure by a factor of r o,con /r i,con , where these are the outer and inner radii of the flux concentrator. Since the ideal remanence magnets can be made maximally efficiency (albeit only at infinite r o ), the desired field in the cylinder bore can be generated with maximum efficiency by fitting a flux concentrator of desired size in the cylinder bore of the magnet.…”

Analytic solution of field distribution and demagnetization function of ideal hollow cylindrical field source

“…(14) and Eqs. (10,11)]. These three equivalent vector expressions for the outer unilateral field are The analytical functions of field distribution of an ideal HCPMA with arbitrary multipole inside and outside the materials are shown above in Eqs.…”

“…The analytic expressions of field distributions B(ρ,ϕ) for an ideal multipole HCPMA are really essential in understanding and designing optimized arrays, since they provide solid mathematical foundation to understand the unilateral field effect of the array. 2 The magnetic field sources for various applications require the perfect unilateral field, [3][4][5][6][7][8][9][10] the analytic descriptions of the field inside the magnet help us to unravel the origin of complicated magnetization phenomena, such as demagnetization, magnetization reversal, and magnetization vortex occurred in the interior of array materials. 11,12 Halbach derived the analytic field expressions of an ideal multipole array in the cavity by the Biot-Savart law using the method of summing the contributions of the numerous separated segments with orientated remanences.…”