'Antimagnet' Cloak Hides Objects From Magnetic Fields

ananyo writes "Researchers have made a cloak that can hide objects from static magnetic fields, realizing a theoretical prediction they made last year. This 'antimagnet' could have medical applications, but could also be used to subvert airport security. The cloak's interior is lined with turns of tape made from a high-temperature superconductor. Superconductors repel magnetic fields, so any magnetic field enclosed within a superconductor would be undetectable from outside. But the superconductor itself would still perturb an external magnetic field, so the researchers coated its external side with an ordinary ferromagnet. The superconductor tries to repel external field lines, whereas the ferromagnet tries to draw them in — together, the two layers cancel each other out (abstract)."

Comments

Airport security?

[hpa]

"Hey, mind if I take in this superconductor cooler through the checkpoint?"

Re:Airport security?

[Brad1138]

Don't assume airport security adheres to any sort of logic...

Re:Airport security?

[tylerni7]

No look, this is perfect. We convince DHS that the terrorists are trying to develop room temperature superconductors to subvert metal detectors and security checkpoints.

Then, clearly the solution is for DHS to start giving obscene amounts of money to physicists in the USA to develop the technology first! It's pretty much a win-win-win situation.

Re:Airport security?

[Anonymous Coward]

Amazing isn't it? Rea searchers make a breakthrough in practical physics, and all anyone can think about is terrorists!

Be afraid people! There could be one under your bed right now!

MRI

[nschubach]

If I understand correctly, they should be able to envelope something like an MRI so that you don't have to worry about metal bits carried into the room?

Re:MRI

[Anonymous Coward]

It renders the object invisible to static magnetic fields. MRI utilizes rapidly changing magnetic fields to encode position. This is still a problem.

Tinfoil hat replacement

[Anonymous Coward]

Finally, a tinfoil hat replacement. Everyone knows that some aliens use magnets and not EM waves.

High temperature superconductor, misleading

[mark-t]

Because it's not "high temperature" in any sense that would be understood by the term.

It's called high temperature because it's significantly hotter than temperatures where superconductivity occurs in ordinary metals (around 30K). But even the highest temperature at which superconductivity has ever been observed is still freakin' cold... over a hundred degrees below 0

Until room temperature superconductivity is discovered (an enormous breakthrough in physics that would have countless applications), nothing's getting by airport security with this mechanism.

Re:High temperature superconductor, misleading

[theshowmecanuck]

That was my first thought. But this might end up being a good prod to get true high temperature superconductor research a super boost. One of the main methods used to detect submarines in the military are magnetic anomaly detectors usually attached to a plane or helicopter. The aircraft don't even need to dip them in the water, just fly over and look for magnetic anomalies (granted the sub needs to be fairly close... but I'm not sure if the military tells anyone what counts as really close). So the crux is that if this will help hide their subs, DARPA and the military might be inclined to shovel piles of money into high temperature superconductors. Although I'm sure they have financed this in the past, this direct applications of stealth for submarines could help with an improved cash flow (or maybe this project is financed this way already.... ?). mmmmm blah blah blah ... profit! Or something like that.

Protect magnetic storage?

[danaris]

So...is this something that could someday be used to protect magnetic storage media from accidental (or even deliberate) exposure to magnetic fields?

Dan Aris

Re:No problem for airport security

[jdgeorge]

But now, why are people so concerned about airport security anyway? The invention has no relation to it.

They're not really concerned with airport security. Slashdotters desperately crave upward moderation. Posting a clever remark related to a popular meme is the easiest way to satisfy that desire.

Submarines

[tsotha]

This could be a big deal in submarine warfare if they can get the temperature up. With the advent of AIP, navies are having to rely on second-string technologies like Magnetic Anomaly Detectors.

Re:This solves what? New?

[50000BTU_barbecue]

I was about to mention mumetal, but its claim to fame is very high permeability. It doesn't repel magnetic fields, it Shamwows them. I suppose if the mumetal is saturated from the inside, then it doesn't hide the object from an external field. Although it takes a lot to saturate properly treated mumetal.

Old man story time. My Tektronix 547 CRT oscilloscope has its CRT encased in a mumetal shield. I got a powerful magnet and put it on the side of the case, the trace didn't budge at all. Great stuff. Of course, mumetal loses its properites if it's dinged, deformed or otherwise mechanically abused.

Not just the rich

[mcrbids]

Anybody who has their own plane pretty much does whatever they want. I've landed my plane at large airports (EG: Oakland, CA) with extensive security lines for commercial flights, and driven my car out to the plane in order to load it. The only credentials I need are the keys to a plane and maybe a driver's license.

I've landed my private plane at big airports in order to hook up with commercial flights, and it's truly absurd to land, walk in off the tarmac, be personally greeted at the private aviation side of the airport, and then take a shuttle to be treated like a potential criminal in a cattle stock yard. This affords me very little respect for the TSA.

You don't need to be a Fortune 500 CEO to have a private plane, the actual cost to own (especially for a time share aka "flight club") can be similar in cost to owning a recent model car.