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Electron/charge flow

  1. Jul 14, 2008 #1
    How may one stop the flow of free electrons in a direct current unshielded wire? Obvious answers like turn off the power or cut the wire will not be responded to!
  2. jcsd
  3. Jul 14, 2008 #2
    If we assume the current is flowing in an infinitely long straight wire, just apply an electric field in the reverse direction of the flow of the current which is sufficient to stop them.

    Of course this is too vague an answer, there are classical assumptions in it, and you cannot really completely stop them.

    And may I ask you why all the trouble?
  4. Jul 14, 2008 #3
    Thanks for your answer. I am looking for anyone with prior research in this area. I'm trying to stop (jam) electron flow in dc circuits and wire to stop Improvised Explosive Devices (IEDs) from detonating and killing our Soldiers.

    I need to do this at far field distances on the order of 300 to 500 meters continuously employing complex electromagentic fields at multiple frequencies with sufficient intensities, i.e., less than 1000 watts, to prevent electron flow. in unshielded copper core, insulated or uninsulated conductors.

    This is a real world problem.
  5. Jul 14, 2008 #4
    That will not work in any physics I know.
    What is the plan? - send the wire through a hole in a large positive plate then through a hole in a negative plate with the plates charged by an independent circuit. Turn the electric field charge up as large as you like, I’ll grant you there won’t be a single free electron finding their way down to the negative plate – but the moving electrons confined to the wire that are part of the circuit the OP is working with will not care a bit the field will not control or stop them.

    Even if large numbers of electrons arc through the wire shorting out the gap between the plates such that the physical DC current electrons that are passing the positive plate are all drawn off in an arc to it; the arc from the negative plate will supply electrons to go replace them and the OP will not know of the exchange. At best it could melt the wire but that is no better than a switch & not allowed.

    Winding the wire around a solenoid and applying an increasing magnetic field would work, but only as long as you could continue a uniform increase in the field. It would build a DC voltage across that segment of wire to block the potential that was moving the electrons. But magnetic field cannot increase forever - stop and the current will resume let it collapse and it is given an unwanted boost. Not going to work.

    As to your real world problem – IMO you will not find an AC solution no matter what the frequency to block the DC signal in a wire strung across a field. Easier would be trying to trip the IED early with a distant impulse signal but I wouldn’t want to use something like that. I’d expect the IED’s would to be redesigned to trigger automatically on a stronger nearby impulse. Seems to me detection is the first key.
  6. Jul 14, 2008 #5

    All of your physical answers are used now with minimal impact.

    Furthermore, this needs to be in quantum physics but someone moved it to classical physics.

    So, the question still remains. How does one stop electron flow in a wire attached to a battery through a switch and on the other end an explosive or electronic circuit? When someone presses the switch, the current flows and a bomb goes off.
  7. Jul 15, 2008 #6
    Well yah duh -- that's what I said if you read it.

    And the question is resolved you prevent the action of the switch before activation not after.
    First detection;
    then preemptive destruction of the IUD;
    leaving and open circuit with nothing for the DC current to do.
    There is no quantum solution or issue here.
  8. Jul 15, 2008 #7


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    Science Advisor

    An alternating magnetic field of significant power would generate a charge in the wiring, which should fry the reciever or send a signal to it, detonating the IED. That's kind-of the opposite o fwhat you asked for, but it accomplishes the job.

    Hey PFers, doesn't an EMP scramble the electrons in wiring, so that the wire no longer conducts electricity? But that still doesn't help you locate the thing, so you've still got a big load of unnexploded ordinace lying there undetected.

    As RandallB says, detection should be first priority. If the alternating mag-field sets off devices, then that would certainly reveal their location; just put the field generator a safe distance ahead of convoys etc.
    Last edited: Jul 15, 2008
  9. Jul 15, 2008 #8
    In the real world, you are right that it will not work. But in the physics of frictionless surfaces, and massless pulleys, and wires flying in space with a current on them without a power supply and constant electric fields without a source it may have worked.

    And I already told you that it was too vague an answer what is all the ranting about?

    Anyway sorry for my non applicable answer but I have no idea about the real world problem at hand, as you have said you really need an expert on the subject and that would mostly likely be an electric/electronics engineer, who has experience on the particular subject at hand.


    Oh, you could also send the blueprints of the particular IED or IEDs you are focusing on to someone you trust or think is qualified enough to tackle the solution (of course if this is not confidential information). It would make your work and the helper's work a lot easier. maybe you cannot stop the free electron movement but disturb another part of the IED.
    Last edited: Jul 15, 2008
  10. Sep 30, 2008 #9
    Try an intense Ion field!
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