Types of dipoles and their fields

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    Dipoles Fields
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Discussion Overview

The discussion revolves around the nature of electric and magnetic dipoles, their fields, and the conditions under which these fields exist. Participants explore concepts related to electromagnetism, including the generation of electric and magnetic fields by various types of dipoles, and the distinctions between electric and magnetic dipoles.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether an electric field exists in a non-moving magnetic dipole and whether a magnetic field exists in a moving electric monopole.
  • Another participant asserts that a non-moving magnetic dipole does not generate an electric field, while a moving electric monopole does generate a magnetic field, referencing the Lienard Wiechert potentials.
  • A third participant clarifies that fields are generated by dipoles and exist in the surrounding space, explaining that a moving magnetic dipole changes the magnetic field and generates an electric field according to Maxwell's equations.
  • There is a discussion about the distinction between electric and magnetic dipoles, with one participant suggesting that the difference lies in the distance between poles, while others clarify that magnetic dipoles are formed by current loops and electric dipoles by separated charges.
  • One participant expresses confusion regarding the representation of field lines in diagrams of current loops, noting discrepancies in sources about whether the lines represent magnetic potential or magnetic fields.

Areas of Agreement / Disagreement

Participants express differing views on the conditions under which electric and magnetic fields are generated by dipoles. There is no consensus on the interpretation of field lines in diagrams, indicating ongoing uncertainty and debate.

Contextual Notes

Some statements made by participants depend on specific definitions and assumptions about dipoles and fields, which may not be universally agreed upon. The discussion reflects various interpretations of electromagnetic theory without resolving these interpretations.

Isaac0427
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Hi guys! Sorry for all the questions on electromagnetism. My understanding is that an electric field exists in electric monopoles and dipoles, as well as moving magnetic dipoles, and magnetic fields only exist in magnetic dipoles and moving electric dipoles. Is this correct? There are 2 parts of that that I am not sure about: Is there an electric field in a non-moving magnetic dipole, and is there a magnetic field in a moving electric monopole? Thanks in advance!
 
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Isaac0427 said:
Is there an electric field in a non-moving magnetic dipole
No. You have to have a changing dipole.

Isaac0427 said:
is there a magnetic field in a moving electric monopole?
Yes. This is described by the Lienard Wiechert potentials.
 
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There is a problem in the way you stated it. The fields don't exist "in" the dipoles, etc., but are generated by, and exist all round them, in empty space. A moving magnetic dipole generates an electric field in the following way. The moving magnetic dipole changes the magnetic field at any given point in space, and the changing magnetic field generates an electric field according to Maxwell's equations. Whether a stationary magnetic dipole generates an electric field depends on how the magnetic dipole is structured. For example, a rotating charge is a magnetic dipole, and it generates both a magnetic field and an electric field. An electric monopole is just a point charge, and a moving point charge does generate a magnetic field.
 
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DaleSpam said:
No. You have to have a changing dipole.

Yes. This is described by the Lienard Wiechert potentials.
Thank you.
 
Ok, and jut to make sure, the difference between a magnetic and electric dipole is if there is any distance between the 2 poles. Correct?
 
No. Magnetic dipoles are formed by small loops of current. Electric dipoles are formed by positive and negative charges separated by a small distance.
 
DaleSpam said:
No. Magnetic dipoles are formed by small loops of current. Electric dipoles are formed by positive and negative charges separated by a small distance.
Then how can a 2-sided magnet be a magnetic dipole?
 
Isaac0427 said:
Then how can a 2-sided magnet be a magnetic dipole?
Ok. I see what I got wrong. What is really misleading me are the pictures of current loops. They all draw the same field lines, however some sources say that the field lines show the magnetic potential, and some say the field lines are showing the magnetic field.
 

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