Current producing electromagnetic force

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Discussion Overview

The discussion revolves around the phenomenon of magnetic fields produced by electric currents in conductors. Participants explore the underlying causes of these magnetic fields, referencing classical theories, relativistic effects, and philosophical implications of understanding magnetism.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants inquire about the fundamental cause of magnetic fields generated by current-carrying wires, questioning what occurs at a microscopic level.
  • One participant suggests that the superficial answer involves Maxwell's Equations but acknowledges the deeper philosophical question of what a magnetic field truly is.
  • Another participant expresses skepticism about the notion that the cause of magnetism is entirely unknown, suggesting that relativistic effects related to the motion of charged particles may explain magnetic phenomena.
  • A different viewpoint posits that magnetic fields arise as relativistic effects of electric fields, with the strength of the magnetic field depending on the speed of the moving charges.
  • One participant critiques the reliance on philosophical explanations, arguing that while the mechanisms may not be fully understood, there are theorized answers that should not be dismissed as completely unknown.
  • Another participant presents a mathematical approach to understanding forces between moving particles, proposing that Coulomb's force can be used in the context of relativity without needing to postulate magnetic fields or Lorentz's force directly.

Areas of Agreement / Disagreement

Participants express a range of views, with no consensus on the fundamental cause of magnetic fields. Some argue for relativistic explanations, while others emphasize the unknown aspects of magnetism, leading to a contested discussion.

Contextual Notes

Participants note the limitations of current understanding, including the challenge of defining fundamental causes at the microscopic level and the circularity of some definitions related to current and magnetic fields.

Who May Find This Useful

This discussion may be of interest to those exploring the foundations of electromagnetism, relativistic physics, and the philosophical implications of scientific understanding in physics.

  • #31
Thank you very much. I understood it. Sorry for my english, but what is net effect? So moving the electron's electric field will have the strongest strength because of its speed of motion?
quote from phys.lsu.edu

Electrons, spinning as they orbit the nuclei of atoms, create magnetic fields. The direction of spin of each electron determines the direction of the magnetic field surrounding it.

I http://gickr.com/results2/anim_fa2cfba7-13bf-5784-7155-43e7058b1574.gif"
 
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  • #32
waht? dfs
 
  • #33
what? Can you tell me why the direction of spin of each electron determines the direction of the magnetic field surrounding it?
 
  • #34
In classical electrodynamics, a spinning object is like a loop of current, which produces a dipole magnetic field:

Magnetic field of current loop

In quantum electrodynamics... ehhh... I'll let someone else tackle that. :rolleyes:
 
  • #35
jtbell said:
In classical electrodynamics, a spinning object is like a loop of current, which produces a dipole magnetic field:

Magnetic field of current loop

In quantum electrodynamics... ehhh... I'll let someone else tackle that. :rolleyes:

I am interested why the direction of spin of each electron determines the direction of the magnetic field surrounding it when the electric field lines are all same around the electron? So if it contracts itself when it moves from the front and back side, no matter which direction it moves the magnetic field will be same.
 
  • #36
  • #37
jtbell said:
Do you know about the right-hand rule for magnetic fields?

Magnetic fields of currents

I know the right-hand rule very well. But why it is like that? IT must be logical staments. What would you understand if somebody tell you: " the current is going into one direction and the magnetic field in other? "
 
  • #38
I suspected that you might ask that question! :rolleyes:

It comes from Ampere's Law, one of Maxwell's four fundamental equations for electric and magnetic fields. In differential form:

\nabla \times \vec B = \frac {\vec J} {\epsilon_0 c^2} + \frac {1}{c^2} \frac {\partial \vec E} {\partial t}

The "\nabla \times" is the "curl" operator. It has a specific "handedness" which leads to the right-hand rule for the magnetic field \vec B.

More stuff about Maxwell's Equations

Now, I'm going to guess that your next question will be, "Why is Ampere's Law like that?" which is equivalent to asking "Why are Maxwell's equations like that?"

My answer to that question is basically the same one that I've already given twice before, to similar questions:

https://www.physicsforums.com/showpost.php?p=1370588&postcount=4

You probably won't be happy with that answer, but it's the best I can do. :frown:
 
  • #39
Can somebody explain better and fundamental the creating of magnetic field around the electrons and its direction? what I see you are familiar with this, please help. Thank you very much, all.
 
  • #40
help pleaseeee.
 
  • #41
For an electron at rest, there is a Coulomb electric field and a magnetic dipole magnetic field, each given by standard textbook equations.
If the electron is moving with constant velocity v, a Lorentz transformation will give the E and B fields of the moving electron. This is done in advanced textbooks. It is a bit complicated because E and B are part of a second rank tensor, and the r coordinate also has to be Lorentz transformed.
 
  • #42
Why you thing that the electric field lines (electric force) will be
compressed?

If electric field lines are homogeneous space (seam) bonded to the
heterogenous seam of the 'particle',
{Or each the 'boundary condition of the other}
then homogeneous space, unlike
heterogeneous space, permits "two, or more, points to be in the same
place at the same time
(xref: Einstein - Botzmann vs. Fermi - Dirac statistics).

Therefore when [exterior sound] the
heterogeneous seam (boundary condition, fermion, 1/2 spin,
only one point in anyone place at one time) is
'displaced', it compresses the homogeneous space against itself. Since
homogenous space permits two points to be in the same place at the same
time, to what degree (xref: elasticity), or since homogeneous space
can be actively homogenous by definition seeking for all points in that
direction, or seam, or space, to actually be in the same place at the
same time, or how close to that ideal symmetry, THEN you would expect a
compression of the 'field' upon motion of the 'charge'.

I hadn't thought to be able to express it that way until your
question. Thanks.

But E-M charge, unlike gravity, is 'reverse' homogeneous, or heterogeneous, to itself, except 'opposite' charges are actively homogeneous to one another while remaining passively homogeneous to all other E-M neutral points . So besides the 'local' infinity of Euclid's zero dimensional point, is there a 'distant' infinity where [^] all the horizons meet? {But they are not parallel}. Is that the 'other side' of the local, zero dimensional, infinity? Is that what
E-M charge 'converges upon' regarding 'like' charge?

Rigid vs. elastic

Elastic in which direction on which side of the 'curve'? Deviation
from perfect symmetry expressed as a 'curve'.
 

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