Ah, I thought it might be an article about the magnets that the Canadians literally dropped on submarines! <a href="https://warisboring.com/nato-bombed-soviet-submarines-with-tiny-annoying-magnets-ba11cfb5578d" rel="nofollow">https://warisboring.com/nato-bombed-soviet-submarines-with-t...</a>
If this works, that would be cool. However, these defense contractors are incentivized to make it seem like something is working so that they beat other contractors to follow-on funding. That doesn't necessarily mean that they are close to making it production-ready for a Navy boat.<p>SQUID is tough technology. It takes liquid nitrogen or liquid helium to get them cold enough to superconduct. A tank of liquid nitrogen is easy enough to take on a boat, though.<p>The devices are so sensitive that you can rotate a cheap one 90 degrees and easily measure the earth's magnetic field. Advanced ones are used to measure brain wave activity. My concern is that SQUID devices are so sensitive that they cannot be stabilized enough on a boat in the ocean to prevent noise (from Earth, boats, gyroscopes, liquid nitrogen pumps, etc) that would make it able to consistently detect the Debye effect.
This may be an incredibly stupid question, but I know they used gravimeters to map the ocean floor on subs.<p>And I recall an anecdote of snow fall on a roof effecting their results in a lab, could you possibly use them to detect other subs.
From space... <a href="https://en.wikipedia.org/wiki/Swarm_(spacecraft)" rel="nofollow">https://en.wikipedia.org/wiki/Swarm_(spacecraft)</a>
My computer science teacher in high school was a sailor in the Soviet Navy. He alluded to something like this being used. That would have been in the min 90s or so. At that point we weren't part of the empire so he probably didn't care about keeping the secrets about it.