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Effect of EMP on electrons. And other EMP related questions.

  1. Jun 17, 2005 #1

    T10

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    What exactly happens to electrons in presense of an EMP field?

    Say you have a flashlight that is switched on, my general assumption is that if some sort of an EMP device goes off, the flashlight will turn off. Why ? Does the battery get discharged in a fraction of a second? If not, why won't the electrons flow then, when the chain is closed?

    On top of that I remember reading a few times from various sources that during Nucular Bomb testing, EMP effect was provailant for more than 20 minutes after the initial explosion. How? Take an electro magnet for example, turn it on, place a paper clip to it, the clip will be held up. Turn the magnet off and the clip will fall, it wont be stuck up for the next half our (Unless of coarse the magnet becomes magnetized).

    Or does the EMP effect take so long to dissapear because of all the radioactivity still in the air?
     
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  3. Jun 17, 2005 #2

    Meir Achuz

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    I give up. What is EMP? I need it to turn off my flashlight.
     
  4. Jun 17, 2005 #3

    T10

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    electro magnetic pulse
     
  5. Jun 17, 2005 #4
    Do you know what ordinary light (and radio waves, and x-rays and all other stuff on the EM spectrum) is? It is a packet of energy of the electromagnetic field. An EMP, if you will.
     
  6. Jun 20, 2005 #5

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    Yes, light, infrared, xrays, gamma etc, all part of the electromagnetic spectrum.

    However, last time I shined a flashlight onto a bulb it did not turn off, so what range of the spectrum is the EMP in? What exactly is being emited to distrupt electron flow? And as to the original question, why does electron flow become disrupted? Or if whatever EMP is, if it is in the high energy spectrum, do such effects happen with all the high energy rays? (Last time I got an xray, I am pretty sure my watch still worked hahaha).
     
  7. Jun 20, 2005 #6

    ZapperZ

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    An "Electromagnetic" wave (such as light and other EM radiation), by definition, has both "electric" and "magnetic" fields. These fields oscillate in space and time. Since charge particles are affected by electric AND magnetic fields, it stands to reason that EM radiation will affect charged particles. And it does! A high-powered laser shot through a plasma can cause a "wake" especially in the "blow-out" region. This is a unique technique in an accelerating scheme[1]. We also use RF fields as accelerating fields in waveguides and LINAC, which is the most common method used in particle accelerators.

    Zz.

    [1] http://accelconf.web.cern.ch/AccelConf/e96/PAPERS/ORALS/FRX03A.PDF
     
  8. Jun 20, 2005 #7

    Meir Achuz

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    An EMP due either to lightning or a power company accident can cause a short circuit in electrical equipment or burn out a connection or damage a component, any one of which could stop operation, temporarily or permanently. Teller's idea was to use an EMP from a modified hydrogen bomb to destroy a missile, but I can go into that.
     
  9. Jun 20, 2005 #8

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    Thanks ZapperZ, I did have the general understanding of how particle accelerators worked (akin to maglev trains and so forth), but since you did mention it, trying to put the two together, in the very basic general assumption, an emp would "magnetically" grab onto the electrons moving in the circuit, and disrupt the flow? Or would the electrons still flow just fine, and the EMP would just mess up the EM field running on the outer surface of the wire/circuit board path/whatever? Most likelly both at the same time :tongue2:

    Come to think of it, that makes sense. :smile:

    Thanks!
     
  10. Jun 20, 2005 #9
    If your flashlight was powerful enough, then the light it was emitting would short circuit any electronics through which it passed.

    Enormous electric and magnetic fields. These fields propagate outwards as a wave pulse. If the electric field is strong enough, it creates an appreciable voltage in the circuit, damaging it.

    Light and radiation are electromagnetics wave-pulses, and above a certain level of power they are strong enough to destroy circuits. The term "EMP" seems to be reserved for these high-powered, destructive wave-pulses.
     
  11. Jun 21, 2005 #10

    T10

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    That is exactly what I was looking for, thank you.
     
  12. Jun 21, 2005 #11
    I am very curious aboot EMP's in general, where did you here that the effect may last for ~20 minutes or so?
     
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