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Superconductors and Space

  1. Dec 29, 2014 #1
    This might be another silly question but here it goes;

    I was reading how " A superconductor excludes the lines of magnetic force" http://www.aip.org/history/mod/superconductivity/01.html and I'm wondering if a giant superconducting magnetic field could help protect spaceships/space stations by deflecting charged particles? It's not a totally impractical question considering how cold space is it shouldn't be hard to maintain a large superconductor . . .


    Regards,
    JDM
     
  2. jcsd
  3. Dec 29, 2014 #2

    OmCheeto

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    (bolding mine)

    I think that's what caught me off guard, the first time I read it, many years ago.
    It has since been revised:

     
  4. Dec 29, 2014 #3

    Drakkith

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    That's a good question. Since the field is so small in size (compared to the Earth's field), it would probably have to be very powerful to have a noticeable impact on relativistic charged particles. Unfortunately I don't know any details.
     
  5. Dec 29, 2014 #4
    Can't sleep tonight [again] so I'll wonder aloud;

    If superconducting fields can deflect relativistic charged particles I wonder if a funnel shaped superconductor could channel those particles to fuel a solar sail . . .

    JDM
     
  6. Dec 29, 2014 #5

    Drakkith

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    Solar sails don't work off of charged particles. Besides, relativistic particles tend to go through things rather than simply impact and accelerate them. This tends to damage the material as well.
     
  7. Dec 29, 2014 #6

    OmCheeto

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    I just finished reading a paper on this problem:
    RADIATION HAZARD OF RELATIVISTIC INTERSTELLAR FLIGHT
    by Oleg G. Semyonov

    He lists some very good ideas:
    Water, aluminum, titanium, and magnetic shielding.
    The magnetic shield requires an electron stripper to be effective.

    His last line seems hopeful:

    His graph "b" on page 4 is interesting. With no shielding, at v = 0.1c, the radiation level is 90 REM/sec. Which from my memory, yields an LD-50 in only 5 seconds!

    Hmmm....
    0.1c = 30,000,000 m/sec
    vessel radius = 5 m
    vessel frontal area = π*102 = 78.5 m2
    interstellar composition(from Oleg's paper) = 89% hydrogen + 10% helium + 1% other
    interstellar density = 2E5 atoms/m3
    hydrogen to deal with = 4.71E14 atoms/sec
    mass of hydrogen atom = 1.66E-27 kg
    Just calculating for the hydrogen, we get 0.000000000000782 kg collected or deflected per second.
    Doesn't sound too difficult.

    I do like the idea of collecting the hydrogen though.
    Someone should figure out what the propulsive effect would be if we used particle accelerators to use them as thrust material, at say, 0.99c.
    It seems such a waste to just throw things away.
    But then the ship would accelerate to relativistically significant speeds, and then things would get way over my head.
    Never mind.

    hmmm.....
    γ = 1/√(1-v^2/c^2) = 7.09 @ 0.99c
    mass of vehicle = 320000 kg (10 x a Greyhound bus. We're going to need a small nuclear reactor)
    KE of hydrogen propellant = (γ-1)*mc^2 = 429,000 joules
    Δv of vessel per second = √(2*ke/m) = 1.64 m/s
    Time to accelerate to 0.2c = 7 months.
    yup. Way over my head.
     
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