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Would it be possible to create a constant EM field that disrupts electronics within it in a similar manner to the way an EMP from a nuclear blast does?

Or would it be possible to have a planet where the magnetic field of the planet is strong enough to prevent electronics from working on all of the planet or in certain areas of the planet?

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    $\begingroup$ First, you don't want it to be constant, that would require enormous amount of energy, better to have it "pulsing". Second, electronic devices inside a "Faraday cage" will continue working. $\endgroup$
    – Alexander
    Commented Oct 6, 2017 at 22:16
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    $\begingroup$ The entire point of an EMP is that the field is not constant. A strong variation in the EM field is dangerous because it creates big currents in any conductor through electromagnetic induction. Faraday's law says that the induced current is proportional to the speed of variation of the field; a constant field will not induce any current. $\endgroup$
    – AlexP
    Commented Oct 6, 2017 at 22:26
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    $\begingroup$ A pulsar near to your solar system could have interesting effects, maybe only causing EMPs at one season per year. $\endgroup$
    – mviereck
    Commented Oct 6, 2017 at 22:59
  • $\begingroup$ @mviereck Good idea or perhaps for a few days a year the sun shields the planet from the interfering pulsar EM radiation. $\endgroup$
    – KalleMP
    Commented Oct 8, 2017 at 5:29
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    $\begingroup$ @KalleMP Also, the pulsar may have its own orbit around a near star (or another sort of cycle) and its EMP only targets the planet at some points of this cycle. $\endgroup$
    – mviereck
    Commented Oct 8, 2017 at 14:36

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Would it be possible to create a constant EM field that disrupts electronics within it in a similar manner to the way an EMP from a nuclear blast does?

As several comments have pointed out: yes, a constant EMP would be impossible. However, a device with consistent EMP-like effects, is certainly possible.

An EMP is an ElectroMagnetic Pulse. This works due to the fact that a change in current, causes a change in magnetic flux, and a change in magnetic flux causes change in current (Faraday's law).

An EMP works by creating a powerful magnetic pulse (fluctuation), causing a change in current in an electronic device. Now, if you wanted to make this consistent, you would merely have to constantly fluctuate the magnetic field, causing a constantly fluctuating change in current.

Or would it be possible to have a planet where the magnetic field of the planet is strong enough to prevent electronics from working on all of the planet or in certain areas of the planet?

Unfortunately, a planet's magnetic field is (fairly) constant. Because of this a large amount of magnetism coming from a planet wouldn't stop electronics from working. Despite this, @mviereck pointed out in the comments, a pulsar is a natural phenomenon that creates an immense amount of magnetic field, while rotating around its axis. This is, basically, a giant EMP.

However, as @Alexander pointed out, either a large pulsating EMP, or a pulsar could be easily overcome by using a faraday cage.

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  • $\begingroup$ Do you know how I could figure out how much energy would be required to power such a device to generate consistent EMP pulses over a given area? $\endgroup$
    – Jonathan
    Commented Oct 8, 2017 at 19:19
  • $\begingroup$ @Jonathan Short answer: A lot. I'm not a physicist, but I'll take my best shot at getting you a number :) $\endgroup$
    – user39278
    Commented Oct 8, 2017 at 23:38
  • $\begingroup$ Could a solar flare cause an EMP, too? $\endgroup$
    – mviereck
    Commented Oct 17, 2017 at 10:24

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