Can a time-varying magnetic field emulate the electric field of a point charge?

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Discussion Overview

The discussion centers around whether a time-varying magnetic field can replicate the electric field produced by a static charge distribution. Participants explore the relationship between magnetic fields generated by current-carrying wires and the electric fields associated with static charges, considering different geometries and conditions.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant suggests that a time-varying magnetic field from an AC current could induce an electric field, but questions whether this induced field could emulate the electric field of static charges, particularly in straight wire geometry.
  • Another participant asserts that magnetic fields and electric fields are fundamentally different effects, implying that one cannot emulate the other.
  • A further contribution clarifies that the electric field generated by a time-varying magnetic field (vortex electric field) is distinct from that produced by static charges (electrostatic field), highlighting their different mathematical properties (zero divergence vs. zero curl).
  • A participant acknowledges the distinction between the two types of electric fields and appreciates the clarification provided by another participant.

Areas of Agreement / Disagreement

Participants express disagreement regarding the possibility of a time-varying magnetic field emulating the electric field of static charges, with some asserting it is not possible while others explore the conditions under which induction occurs.

Contextual Notes

The discussion does not resolve the complexities of how different geometries of current-carrying wires might influence the induced electric fields, nor does it clarify the implications of varying frequencies on the relationship between magnetic and electric fields.

uby
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A point charge generates electric field lines that are radially directed from the source in spherical symmetry. Similarly, a line of charge generates electric field lines that are radially directed from the line of charge in cylindrical symmetry.

Is there any way that a time-varying magnetic field generated by a time-varying current in a wire could emulate the electric field of an assemblage of static charges in the same geometry as the wire?

I suppose the question may be geometry dependent. For a straight wire carrying DC steady current, the magnetic field is time-invariant and generates no electric field outside the wire.

For the same wire carrying AC current with a single frequency, the magnetic field varies periodically and thus generates an electric field (though I have a hard time picturing the direction I believe that this induced electric field would be in the same direction as the original electric field ... parallel to the wire in this case).

For an AC current that has 'higher order' changes in its frequency (i.e. - variation in the variation in electric field), there would be 'higher order' induced electric fields though again always in the same direction of the originally generating electric field in the wire.

Therefore, I do not believe it is possible for a straight wire geometry to generate a radially-outward electric field by induction. Though, I cannot rule out that for other geometries of the current carrying wire that it is impossible. Does anyone have any insight on this?

Thanks!
 
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You are asking if a magnetic field can emulate an electric field? If so, then the answer is no. The two are different effects and act differently.
 
No, the electric field generated by time-varying magnetic field (vortex electric field) is distinct from that from charges (electrostatic field). The former has zero divergence while the latter has zero curl.
 
Drakkith said:
You are asking if a magnetic field can emulate an electric field? If so, then the answer is no. The two are different effects and act differently.

Thanks for your reply Drakkith. No, I was referring to whether the induced electric field caused by a time-varying magnetic field could emulate the electric field of a static charge distribution.

netheril96 said:
No, the electric field generated by time-varying magnetic field (vortex electric field) is distinct from that from charges (electrostatic field). The former has zero divergence while the latter has zero curl.

Thanks netheril, that is a very elegant way of answering my question and is a very helpful method for thinking about this!
 

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