The X-Men need to get their hands on one of these.
Alvaro Sanchez of the Autonomous University of Barcelona in Spain and colleagues propose a way to approximate the impossible stuff by wrapping the cylindrical shell of superconductor in layers of materials that do one job at a time. Some layers are easily magnetized and will essentially pull the external magnetic field lines around the cylinder; those layers alternate with shells of superconducting plates that push on the field, preventing it from coming straight in toward the center. The attracting layer would be made of tiny magnetic particles, like submicroscopic iron filings, mixed into a nonmagnetic material such as plastic.The cloak could handle fields of any shape and any strength within what the superconductor can stand. If the external field gets too strong, the magnetically induced current becomes so powerful that it knocks the superconductor out of its resistance-free state and ruins its field-repelling qualities.
Computer simulations showed that the cloak could work with as little as four layers, but with 10, it would guide a magnetic field nearly as well as a perfect cloak, as Sanchez and colleagues report today in the New Journal of Physics. “It doesn’t need to be a closed cylinder; it can be an open cylinder or open plate, although in this case the magnetic cloaking properties are reduced,” Sanchez says.
The hypothetical device would work as a magnetic cloak by creating a space that is protected from an external magnetic field while at the same time causing no telltale distortion of the field.
