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I Are x-rays from lightnings and magnetism the same effect?

  1. Jul 4, 2018 #1
    Hello!

    In 2010 Richard A. Lovett has published a photo from a ligthning-strike in the national geographic magazine, which shows significant x-ray radiation.

    Obviously a lightning-strike is an electrical current in air (and water).


    In electrodynamics an electrical current in metals generates magnetic fields and (photon based) radio signals.

    My questions:
    1. Are x-rays from lightnings and magnetism/ radio signals basically caused by the same quantum electrodynamics effect related to electrons?
    2. Is the type of photon-wave generated only dependend from the medium, in which the current flows?

    Consuli
     
  2. jcsd
  3. Jul 4, 2018 #2

    jambaugh

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    You're not going to get high frequency electromagnetic radiation like x-rays or even visible light from currents in metals. The x-rays from lightning and from x-ray machines comes from individual atomic excitations. I think lightening simply heats the air hot enough to incandesce with significant x-rays. This isn't surprising given its hotter than the surface of the sun which is itself hot enough to radiate some in the x-ray band.

    X-ray tubes aim an electron beam into a copper or tungsten target and the high energy electrons knock other electrons in the metalic atoms to high excitation. They then emit x-rays as the electrons return to their ground states.

    This is not to say that the generation is not, as with your cell phone antennas, still a matter of moving charges generating em radiation. It's just that the process is atomic instead of merely within the Fermi sea of electrons swimming in the conducting region of a metal.
     
  4. Jul 4, 2018 #3
    If this would be true, the x-ray from a lightning would not be synchronous with the electrical discharge in a lightning-strike, as latest lightning experiments show.

    Consuli
     
  5. Jul 4, 2018 #4

    jambaugh

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    It sound like your reference is better read than I on the subject. [Could you link the actual posting, your quote links to a blank]. But there's only so many fundamental ways to produce x-rays.
    • bound state to bound state electron transitions in an atom (by whatever excitation mode produced the vacancy).
    • free state to bound state electron transitions in an atom.
    • Electromagnetic acceleration of free electrons (which includes e.g. bremsstahlung).
    • Electromagnetic acceleration of non-electron charged particles.
    Likely we can discount acceleration of say protons or nitrogen ions as well as nuclear transitions which are up in the gamma ray spectrum. (Interesting papers on gamma rays from lightning strikes when I did a quick search). I would re-classify the others along causal lines:
    • Electronic excitation from molecular collisions (gaseous incandescence),
    • Electronic excitation from impinging free electrons (electroluminescence, and plasma incandescence),
    • Electron scattering (bremsstahlung, etc were the high energy electron is the source)
    I would discount the first of these latter three cases. Naturally at x-ray energies we have ionization and plasma instead of gas. My intimation was plasma incandescence but you're reference seems to imply scattering effects, i.e. bremsstrahlung.

    Beyond that... my final answer to your queries to the best of my knowledge is:

    1.) yes it's all always the same quantum electrodynamics. (bound transitions demonstrate more of the quantum aspect)
    and
    2.) The only dependency with respect to the medium is going to be some spectral dependency from that radiation resulting in bound electron transitions but less so when dealing from ionized atoms reabsorbing free electrons. And, I think, very little dependency on the type of medium beyond density when it comes to bremsstahlung.
     
  6. Jul 4, 2018 #5

    davenn

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    Yes, agreed, this article, one of the OP's links .....

    https://news.nationalgeographic.com/news/2010/12/101223-lightning-x-rays-camera-science-technology/

    .... speaks of the x-rays being generated by the lighting strike on the metal tower and no comments about anything being generated with interaction with atmospheric atoms present along the strike path

    UNFORTUNATELY, they didn't show one of their x-ray images

    The lightning strike on the metal tower is much the same as this process you stated, and I can see how that fits......

    A "beam/stream" of very high energy electrons striking metal


    Consuli ... that statement needs correcting, just so you understand correctly

    A DC electrical current can generate a magnetic field ... but NOT an EM emission aka radio waves ( Electromagnetic)
    An AC electrical current can generate both a magnetic field and an EM emission

    not sure how you come to that conclusion ??


    X-rays and radio signals are both EM emission

    magnetism is not

    not a well structured question

    The type of EM (photons) generated is related to the energy levels injected into the system

    As @jambaugh said earlier.....
    HI energy excitation is required
     
    Last edited: Jul 4, 2018
  7. Jul 5, 2018 #6
    What does that effectively mean, then?

    A lightning strike is a DC discharge. Does it mean, it cannot generate an EM wave emission [just a single (x-ray) impuls]?

    Consuli
     
  8. Jul 5, 2018 #7

    davenn

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    it's a lot more complex than a plain DC voltage as seen from battery or an AC to DC power supply
    The majority of the lightning discharge is in a single direction but once the channel has been formed, there can be
    a number of oscillations back and forward

    But even the initial pulse of the lightning strike produces a large pulse of EM …. this can be heard on any am broadcast radio receiver.
    The same thing happens when you close the switch on a DC or AC power supply
    Have you ever wondered why a light turns on the moment you flick the switch ? There is an initial pulse of EM energy that goes around the circuit
    Electrons don't travel fast enough to produce the near instantaneous effect that is observed

    The X-rays are produced by a different method, that was explained in an earlier post by jambaugh

    Dave
     
  9. Jul 6, 2018 #8
    And this isn't a contradiction to

    ?

    If not, could you go further into detail, why this isn't a contradiction?

    Consuli
     
  10. Jul 6, 2018 #9

    davenn

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    no it isn't a contradiction

    it's the same thing …. as I said earlier .... a beam/stream of high energy electrons striking a metal target

    as Jambaugh stated in a previous post of his


    maybe you missed his other comment ??

    Lightning appears to have 2 known ways it produces x-rays

    1) bound state to bound state electron transitions in an atom (by whatever excitation mode produced
    the vacancy).

    when it hits a metal target … a plane or something on the ground, as in that metal tower the rockets launched from in one of your links

    2) Electromagnetic acceleration of free electrons (which includes e.g. bremsstrahlung).

    which is occurring within the clouds
     
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