Hospitals, power grids, aerospace systems, and scientific laboratories all host extremely sensitive technologies that allow the facilities to do what they need to do—as long as no pesky, unwanted signals get in the way. That’s certainly easier said than done, but an engineering team believes they may have the most magical-sounding solution ever: an invisibility cloak.
In a recent Science Advances paper, researchers at the University of Leicester in the United Kingdom unveiled a concept for manipulating the flow around an object so that it behaves as if the “object isn’t there,” according to a statement. Similar magnetic “cloaks” had been developed before, but the new concept is the first demonstration of a cloak that works for any type of shape.
“Magnetic cloaking is no longer a futuristic concept tied to perfect analytical conditions,” Harold Luiz, study senior author and an engineer at Leicester, said in the statement. “This study shows that practical, manufacturable cloaks for complex geometries are within reach, enabling next-generation shielding solutions for science, medicine, and industry.”
Hiding from magnetism
As one of four fundamental forces in nature, magnetism is virtually everywhere in the world. Many technologies—hard drives, MRIs, nuclear reactors—manipulate magnetism to some degree, but unwanted magnetic fields can be a serious nuisance, causing signal distortion, data errors, or equipment malfunction, the researchers explained.
Magnetic cloaks rewire the magnetic flow around the cloak such that any external magnetic fields passing by are unable to detect the object under the cloak. Prior to this study, researchers had experienced limited success when attempting to engineer magnetic cloaks. And when they did manage to fabricate one, the cloaks were cylindrical or spherical, “limiting their practical relevance,” according to the paper.
A fluid invisibility cloak
The new concept, however, is surprisingly flexible. The researchers combined superconductors with soft ferromagnets to craft the cloak. In this blueprint, the superconductor element expels incoming magnetic fields, while the soft ferromagnets reroute the superconductors’ distortion of the magnetic field lines into smoother shapes. This tricks an external magnetic signal into thinking there’s nothing there, the researchers said.
That said, this is a paper on the concept, and the team has yet to create a physical version of the cloak. It must also be noted that the superconducting elements of the system only work under extremely cold temperatures, although the researchers do mention in the paper that “this should not undermine their viability, as the cryogenics industry supporting superconducting technologies is already well established.”
“Our next step is the fabrication and experimental testing of these magnetic cloaks using high-temperature superconducting tapes and soft magnetic composites,” Ruiz added. “We are already planning follow-up studies and collaborations to bring these designs into real-world settings.”
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