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Quantum Hall Thruster? (QuantumHallEffect+HallThruster=?)

  1. Feb 5, 2008 #1
    I've heard of the Hall Effect, and I've heard of Hall Thrusters. But then there's also something called the Quantum Hall Effect. Does that mean there could possibly one day be Quantum Hall Thrusters?
     
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  3. Feb 6, 2008 #2

    ZapperZ

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    Have you looked at the actual phenomena beyond just the names given to them?

    Zz.
     
  4. Feb 6, 2008 #3
    Hi Zapper,

    Why didn't I predict this reply from you? :)

    I'm still asking -- can the Quantum Hall Effect be used for propulsion or enhancement of propulsion?
     
  5. Feb 6, 2008 #4

    ZapperZ

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    I don't know why you didn't. Your post were simply inviting such a response, especially when it seems to indicate that you were doing nothing more than shuffling the names around.

    I'll answer that after you tell me how you propose to create a 2D electron transport system in a Hall thruster.

    Zz.
     
  6. Feb 6, 2008 #5
    Graphene could be used as a 2D electron transport system. It's being touted as the best conductor ever, exceeding copper, gold and silver.
     
  7. Feb 6, 2008 #6

    ZapperZ

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    I didn't ask for a 2D system! I asked for how you're going to create a 2D system in a hall thruster.

    Zz.
     
  8. Feb 6, 2008 #7
    Hey, I'm the one asking the question here. Can it be done?
     
  9. Feb 6, 2008 #8

    ZapperZ

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    No.

    Zz.
     
  10. Feb 6, 2008 #9

    Astronuc

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    Please look at the conditions under which the Quantum Hall Effect is observed, then compare those conditions and environment with a those of Hall thruster.

    The Hall effect is generic.

    Consider fusion. The sun and stars produced energy by fusion. Look at the conditions under which that occurs. Then look at the fusion system that people are trying to build on the earth. Both are fusion and subject to the same principles of physics, but they are orders of magnitudes apart in terms of power density, particle density and pressure.
     
  11. Feb 6, 2008 #10
    But the hall effect is observed under conditions of low temperature and strong magnetic fields. I don't see that maintaining a low temperature should be difficult for a spaceprobe, which is isolated in a vacuum. Furthermore, there are newer materials like graphene, which has been found exhibit the Quantum Hall Effect at room temperature!

    http://www.cise.columbia.edu/nsec/research/nuggets.php?subsection=quantum

    I'm wondering if the Quantum Hall Effect could perhaps be used in reverse, so that the flow of electrons would generate a strong magnetic field. That magnetic field could perhaps then be used to accelerate propellant mass.
     
  12. Feb 6, 2008 #11

    Gokul43201

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    No, it can not. If all you want is to make a magnetic field, you'd just use an electromagnet.
     
  13. Feb 6, 2008 #12

    Astronuc

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    The objective is to get the propellant as hot as possible, with a lot of kinetic energy/momentum per unit mass (and mass flow rate).

    Hall effect thrusters are hot.

    Even better, MPD or magnetoplasmadynamic thrusters.
     
  14. Feb 6, 2008 #13
    Well, a magnet based on superconductivity is better than one based on conventional electromagnets. That seems to be the premise of various futuristic maglev concepts.

    The Quantum Hall Effect seems to exhibit an apparently inertia-free ("massless") movement of electrons in the presence of a strong orthogonal magnetic field. Couldn't this "massless" (bosonic? wave-like?) movement be exploited for some beneficial propulsive purpose?

    If the electrons are ejected in a "massless" way, then shouldn't this be independent of action-reaction and conservation of momentum? After all, they are moving along the graphene without any apparent mass -- so if you've lost your apparent mass, then how can can you impart any action-recoil to anything? The electrons would be accelerated to near light-speed, ejected from some electron-gun, and then impact against a "sail" extending out from the gun, thus imparting action-reaction momentum to the entire apparatus.

    Why should the electrons move along the graphene electrode in a "massless" way and not eject from it in a similarly "massless" way?
     
  15. Feb 6, 2008 #14
    Alright, but the hallmark of the Quantum Hall Effect (which graphene shows at room temp) is that electrons move in a "massless", "wave-like" way, sort of like photons.

    So somehow mass-bearing electrons are being given apparent masslessness.
    So from the perspective of the tiny electron, they're getting quite a lot of propulsive benefit, given that their inertial mass is being neutralized.

    Can the wave-like nature somehow be exploited?
     
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