Electrons at rest have magnetic fields

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Discussion Overview

The discussion centers on the properties of electrons, particularly regarding their magnetic fields and the implications of their intrinsic spin. Participants explore whether electrons at rest possess magnetic fields, the nature of their magnetic dipole moments, and the relationship between electric charge and magnetic properties.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that electrons at rest have magnetic fields due to their intrinsic spin and magnetic dipole moment.
  • Others argue that the classical radius of the electron is not relevant for calculating magnetic field strength.
  • There is a proposal to calculate the magnetic field strength of electrons, but the feasibility of such calculations is questioned.
  • One participant raises a question about the relationship between the electron's negative charge and its magnetic dipole moment, seeking clarification on why they do not cancel each other out.
  • Some participants clarify that an electron has a monopolar electric field and a dipole magnetic field, emphasizing the distinction between electric charge and magnetic properties.
  • There is a challenge regarding the validity of a proposed equation related to magnetic fields, with participants discussing the origins and implications of Coulomb's law in relation to magnetism.
  • References to various sources and textbooks are provided to support different viewpoints on the topic.

Areas of Agreement / Disagreement

Participants express differing views on the nature of magnetic fields associated with electrons, the relevance of classical radius, and the interpretation of equations relating to magnetic fields. The discussion remains unresolved with multiple competing perspectives presented.

Contextual Notes

Some participants note limitations in understanding the relationship between monopolar and dipole fields, as well as the applicability of certain equations to electrons as point dipoles.

TruBlu4AU
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It could be that I'm misinformed, but I heard electrons at rest have magnetic fields. I thought that magnetic fields required a charge to be traveling at velocity before a magnetic field would arise. If this is the case could someone help me out?

If an electron has a magnetic field at rest what is its strength? Or to be more specific, if we were to take the classical radius of the electron, 2.8179403267 x 10^-15m, what would the surface force due to magnetism be on the electron if we could somehow shrink ourselves to that size and stand on the electron's surface? Is there anyone who can calculate what that value would be assuming what I heard was correct?
 
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Electrons have a property called "spin".
With this comes a magnetic dipole moment, so an electron is a tiny permanent magnet.
Its magnetic moment has a value of about 10^-23 J/T (Bohr magneton).
 
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Electrons have spin angular momentum and charge, so they do have an intrinsic magnetic dipole moment.

The classical radius thing is meaningless for an electron so there isn't a good answer for your other questions.
 
I see guys, thanks. So electrons are like little magnets then. Is there any way to calculate their magnetic field strength?
 
DaleSpam said:
Electrons have spin angular momentum and charge, so they do have an intrinsic magnetic dipole moment.

The classical radius thing is meaningless for an electron so there isn't a good answer for your other questions.

I've got one more question concerning what was brought up here. If electrons are like tiny magnets with two poles of different polarity why do we view them as charged particles? Maybe there is something here I'm not quite grasping. Here's my thinking, an electron has a negative charge of roughly 1.6x10^-19 C. However, it must also have two poles of opposite polarity(like say the earth). Why don't these poles cancel out and give us a neutral particle? Is there something here I'm misunderstanding?
 
You seem to be mixing up magnetic poles and electrical charge. An electron has a monopolar electric field and a dipole magnetic field. Therefore it has an electric charge but not a magnetic charge (magnetic charges don't exist as far as we can tell).
 
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DaleSpam said:
You seem to be mixing up magnetic poles and electrical charge. An electron has a monopolar electric field and a dipole magnetic field. Therefore it has an electric charge but not a magnetic charge (magnetic charges don't exist as far as we can tell).
Thank you for your reply Dalespam.

If magnetic fields don't have charge then why can we write a Beta field equation as , B=μ0/4π(Q/r2) where: Q= the charge of the field? Which again is the analog in magnetism of Coulomb's law?
 
That equation is not correct. Where did you get it?

Magnetic fields are caused by moving electric charges (electric current), not by separate magnetic charges.
 
  • #10
DaleSpam said:
That equation is not correct. Where did you get it?

Magnetic fields are caused by moving electric charges (electric current), not by separate magnetic charges.

The equation came from Coulomb, the same guy who gave us Coulomb's law F=k(q1q2/r^2).

The law of force between poles was investigated by Charles Coulomb, using the same torsion balance with which he established the law of force between electric charges, and was found to be similar in form to that for charges.

In coulomb's law the the constant of proportionality was found to be k coulomb's constant which is the permittivity of free space. In the other equation the constant of proportionality was found to be μ0/4π the permeability of free space.
 
  • #11
Please provide a specific reference for this equation.

Do you understand the difference between a monopole and a dipole? Gauss law for magnetism prohibits monopolar magnetic sources, but Gauss law permits monopolar electric sources. Thus the electron has electric charge (monopolar), and a magnetic moment (dipole).
 
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  • #12
DaleSpam said:
Please provide a specific reference for this equation.

Do you understand the difference between a monopole and a dipole? Gauss law for magnetism prohibits monopolar magnetic sources, but Gauss law permits monopolar electric sources. Thus the electron has electric charge (monopolar), and a magnetic moment (dipole).

Here's a quick link.
http://www.daviddarling.info/encyclopedia/C/Coulombs_law_for_magnets.html
 
  • #14
TruBlu4AU said:
Here's a quick link.
http://www.daviddarling.info/encyclopedia/C/Coulombs_law_for_magnets.html
Read the third paragraph on that page. It confirms what I was saying.

Note also paragraph four which describes how the following information uses long thin magnets as shown in the figure. An electron is, to the best of our measurements, a point dipole. So the subsequent equations don't apply.
 
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