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Question about EMP

  1. Feb 3, 2005 #1
    Hi everyone,

    I’m a wannabe scribbler of Science Fiction trying to get things right in a story I’m working on...so I thought the best idea was to come and ask the experts and those who know far more than I ever will in a place such as here.

    Ok I’m now done with the flattery, but it will hopefully get me somewhere ;-)

    Basically I’m working with a limited nuclear exchange in space. Is there likely to be enough air in a spacecraft for enough of a Compton Effect to produce a significant EMP or am I looking at needing a planetary volumes of atmosphere to produce anything approaching destructive levels.

    Secondly, with a nuclear produced EMP am I looking at any noticeable effects for those living within such a tin can, other than the destruction of electrical equipment? Are there going to be people electrocuted, because they were in contact with metal surfaces when the blast occurred, would someone who was not touching any surfaces be carrying a charge after the blast or would the limited volumes of atmosphere mean a rapid return to equilibrium?

    Last one... other than the pulse directly fed into a system via antenna and communication dishes, I know that if there is an EMP I’m looking at problems caused by induced currents in long wires due to the low frequencies, gaps in electronic casings acting as wave guides for the higher frequencies. Is protection as simple as disconnecting long wires and having more sensitive electrical equipment in a sealed tin box (though insulated from the box itself)? Would this 'Faraday box(?)' have to be earthed?

    Thanks very much,

  2. jcsd
  3. Feb 3, 2005 #2


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    It's not the air, per se, that causes EMP. There are two requirements for EMP: (1) the existence Compton electrons and (2) a gradient in Compton electrons on the scale of the range of the the photons. E.g. you would have no EMP in a perfectly uniform atmosphere (given a symmetric explosion) because there would be no dipole moment to the charge distribution.
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