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Thread: Electromagnetic fields as barriers

  1. #1
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    Exclamation Electromagnetic fields as barriers

    i need some clarification, electromagnetic fields interact with charged particles as in any particle accelerator, then shouldn't a sufficiently strong magnetic field be able to prevent electrons from moving from one side to the other (the +ve side), if that is true wouldnt that basically hold atoms on one side while allowing them to pass through from the other side, can't we use that to hold an atmosphere in space applications where the isn't sufficient gravity,(given that we have large amounts of energy to generate this field), i ask this because all talk about magnetospheres is about shielding from radiation and solar flares no one ever mentions this.

  2. #2
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    No. It only holds charged particles (ions). Neutral atoms of gas cannot be held that way.
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  3. #3
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    Quote Originally Posted by Noclevername View Post
    No. It only holds charged particles (ions). Neutral atoms of gas cannot be held that way.
    What I'm not sure about is this: while it is true that the atom as a whole is neutral, an electron and proton have the same magnetic moment, but the proton is 2,000 times as massive, so I wonder if a very strong magnetic field could overcome the Coulombic attraction and ionize the gas. I'm sure it would be impractical, but just as a mind exercise I think it's interesting to consider.
    As above, so below

  4. #4
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    There is the plasma window:

    https://www.techbriefs.com/component...tb/briefs/1834

    I think the above article describes it well, but the Wikipedia article has some points too:

    https://en.wikipedia.org/wiki/Plasma_window

    In a plasma window, a magnetic field is used to constrain a hot low density ionized gas. Since it is ionized, the magnetic field can interact with the charged particles. The plasma in turn can block the neutral atoms in air from crossing, or in some cases, they will be ionized as well. The technology is useful in some applications for creating a barrier between atmosphere and vacuum. The downside is that it is very energy intensive, so large Star Trek-like “force fields” appear to be impractical.

    This is different from the effects of a magnetosphere in regards to an atmosphere. The magnetosphere redirects charged particles that can strike atoms at the top of an atmosphere and speed them up enough to cause them to escape a planet. This takes a very long time to have a significant effect, more massive planets will have lower atmospheric erosion, and it also affects lower mass atoms or molecules more (notice that Venus still has a very thick atmosphere).

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  5. #5
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    exactly that is what i was thinking, my idea is that this could be used to hold a bubble of gas and protect it from vacuum.

  6. #6
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    wonderful, but can this be scaled up to contain an atmosphere around an object that lacks the mass required to hold an atmosphere.

  7. #7
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    Quote Originally Posted by Blitzkrieg View Post
    wonderful, but can this be scaled up to contain an atmosphere around an object that lacks the mass required to hold an atmosphere.
    I think that would be extremely unlikely. As I mentioned, it is very energy intensive, which makes larger applications impractical, especially applications where pressure is to be maintained long term. Then there are the hardware requirements - electromagnets and hardware to maintain the plasma. Those would have to be dramatically scaled up as well. And there are the catastrophic consequences if power ever fails.

    A solid barrier seems far more practical to maintain pressure. No power needed, and probably more effective anyway. (I expect there would be some gas escape though a plasma window).

    A plasma window appears to be useful for certain special applications, but conventional pressure vessels would win out for most purposes. It is an interesting technology though.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." — Abraham Lincoln

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