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I Copper and magnetism

  1. Nov 24, 2017 #1
    I have read that, while copper is not magnetic per se, if we have a strong enough magnet, it can interact with copper. This ties in with the fact that all matter can be magnetic if you have a strong enough magnetic field. But I am interested, how strong must the magnet be to interact with such elements, I singled out copper because I am most interested about copper. I have searched the internet, but I was not able to find anything, so I am asking here.
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  3. Nov 24, 2017 #2


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    Are you maybe thinking about using eddy currents from a magnet moving past a piece of copper?

    Otherwise as you say, if you have a huge B-field, you may be able to observe a slight effect on copper, but why bother?

  4. Nov 24, 2017 #3
    I am interested in military stuff. I have studied helmets and if it is possible to add some form of magnetic current to repel bullets. Of course, copper is essential in the jacket of a bullet, so I am interested to see how strong the magnet has to be. I have read something about magnetism, but I dont know much. I will read about it in a few days though so we will see.
  5. Nov 24, 2017 #4


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    Yeah, that doesn't seem to be a good scientific match. Especially since the majority of the mass of bullets is from lead, not from any copper jacket. Have a read through the link that I posted.

    You might have better luck with some sort of reactive armor configuration, although that has its own issues for body-worn armor. Are you familiar with reactive armor?
  6. Nov 24, 2017 #5
    I have yet to really start studying the details. But yes I am familiar with reactive armor. I have not yet looked at it from physics perspective though, I was more interested in tactics, but I have a lot of ideas. So, now I am checking if any of those ideas could work IRL.
  7. Nov 24, 2017 #6

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  8. Nov 24, 2017 #7
    Countless hours of research have been spent by engineers trying to make a better helmet, there is obviously a lot at stake. You might want to study the state of the art and go from there. Magnetic deflection is a dead end I'm afraid. A quick Google search,


    Found this,

    "Whenever you play any kind of war video game of watch any kind of war movie, you might wonder why any of the solders decide to put on protective gear since their opponent’s weapons always seem to be able to easily penetrate their protective covering. However, the United States Army has created and deployed a new kind of protective helmet that can actually stop a moving bullet, including a 7.62x39mm round from an AK-47."

    From, https://www.geek.com/gadgets/advanced-combat-helmet-stops-an-ak-47-head-shot-1536798/

  9. Nov 25, 2017 #8
    I know that the Americans managed to develop helmets that deflect bullets. Weren't the Germans the first to develop those helmets in WW2? The Americans probably developed it further. I am not that familiar with that. I know that, in older versions, if the bullet hits the helmet directly it will penetrate, but if it is a grazing hit, it will be deflected. I was thinking about creating a smaller magnetic field in order to make the helmet less susceptible to penetration. I only got that idea in my head so I came here to ask experts if that is even possible.
  10. Nov 25, 2017 #9

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    It's not possible.
  11. Nov 26, 2017 #10
    Okay, I just wanted to check if my idea was possible.
  12. Dec 3, 2017 #11
    Are you thinking 'eddy currents' as in a car's analogue speedometer ?

    Unfortunately, you would need a very, very strong, widely-extended magnetic field to slow incoming stuff thus. And it would only work on conductors, so mines or IEDs hurling rocks would get through. Sadly, the same problem extends to space-craft versus micro-meteorites...

    ( I've ignored 'swarf catcher' issues... )
  13. Dec 3, 2017 #12
    To be practical it must be more than possible, what ever contraption you make the soldier has to be able to wear it.
  14. Dec 3, 2017 #13


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    Perhaps do some sums... Let's say you need to deflect a bullet 200mm over a distance of 1 meter to get it to miss your head. Make a diagram and calculate or estimate the radius it would have to follow. Then work out the centripetal force required. Bear in mind that Newton's laws say your helmet will experience an equal and opposite force.
    Last edited: Dec 3, 2017
  15. Dec 8, 2017 #14
    People, I am not a physicist, I know physics in theory. I deal with tactics, not physics. This forum is nice and there are a lot of smart people, so I wanted to introduce my ideas to you for you to evaluate from physics' perspective.

    I am interested in something else: can magnets be used to deflect radiation since the magnetic field apparenly can deflect radiation, like the Earth's field. But, I assume that the magnetic field would also attract radiation, so is it usable?
  16. Dec 9, 2017 #15
    To do,


    I do that alot, I assume people will figure out what my writing means. Properly you should make it as easy as possible for someone to understand what your question is?

    I will try and remember that as well.
  17. Dec 10, 2017 #16
    A magnetic field *will* cause charged particles' path to bend. The result depends on the field strength / distribution and the particle mass/energy. Mass spectrometers do this very well, as do particle accelerators. But, you'd need a very powerful magnet with a very extended field. Never mind the power generation requirements, passive shielding is probably lighter. { Hypothetical high-temperature superconductors may help, of course... }

    For size, think of the safety zone around a hospital's NMR scanner, or a scrap-yard's magnetic grab. Now up-scale that zone to a 'track+field' stadium...

    Sang is your magnetic field has no effect on neutral particles, or on high-energy photons such as X-rays and gamma rays. There's scant benefit and possible complications for micro-meteorites. So, you need that heavy passive shielding after all...
    Sorry, given current physics, we've nothing that could serve as a StarTrek / Dune 'deflector field' or 'personal shield'. And, given the momentum issues, such a system may have to be 'active', sensing and countering incident forces like a sky-scraper's 'active mass damper'. Happens such tech would also provide propulsion, artificial gravity, non-contact pumping etc etc. Oh, and several Nobel prizes...
  18. Dec 10, 2017 #17
    The technology of using strong magnetic fields to alter the path of particles does exist!
    However it needs to be several km in size and cooled by tonnes of liquid helium (LHC etc).
    So not very helpful as personal armour.
  19. Dec 13, 2017 #18
    I have asked that since I wanted to know if it was possible to create a suit using magnetism that allow people to work in areas contaminated by radiation, like after an explosion of the nuclear bomb. How strong would the magnetic field need to be for a human to enter a contaminated site, like Chernobyl?
  20. Dec 13, 2017 #19

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    It's not.
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