Magnetic field of a moving charged particle

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Discussion Overview

The discussion revolves around the magnetic field produced by a moving charged particle and whether this moving magnetic field, as observed by a stationary observer, generates an additional electric field. Participants explore various aspects of electromagnetic fields, including the relationship between electric and magnetic fields, the effects of motion, and the implications of special relativity.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • Some participants assert that a moving charged particle creates a magnetic field that a stationary observer perceives, questioning whether this magnetic field generates a new electric field.
  • Others argue that the electromagnetic field around the particle is fundamentally electric, with magnetic characteristics arising from motion, and that no new fields are created.
  • There are claims that the electric field is a fundamental entity, while the magnetic field is a result of the movement of charged particles, suggesting a distinction between the two.
  • Some participants highlight that a changing magnetic field can induce an electric field according to Faraday's law, but debate whether this induced field is separate from the original electric field of the charged particle.
  • Concerns are raised about the terminology used, specifically the phrase "moving magnetic field," with some participants emphasizing that magnetic fields do not move in the same way as particles do.
  • There is a discussion about the interaction between the electric field produced by a charged particle and the electric field induced by a changing magnetic field, with some asserting they are not independent.
  • Participants note that a charged particle moving at constant speed produces a constant magnetic field, which does not generate an additional electric field unless the particle is accelerating.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the relationship between electric and magnetic fields, the nature of fields produced by moving charges, and the implications of motion on these fields. The discussion remains unresolved, with no consensus reached on whether the moving magnetic field produces an additional electric field.

Contextual Notes

Some statements rely on specific interpretations of electromagnetic theory, and there are unresolved questions regarding the definitions and interactions of electric and magnetic fields. The discussion also touches on the implications of special relativity and the nature of fields in different frames of reference.

  • #31
Or maybe your just not getting the answer provided to you.

There is no magnetic field of a moving particle in it's own frame of reference if I even can call it so.
The magnetic field is only to a observer which moves at a different speed than that of the moving particle or is stationary with respect to it.

there is no difference from a static electric field to that of a particle because the field of a single charged particle is fixed in value and is static if that is what you wanted to know.
 
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  • #32
Crazymechanic said:
there is no difference from a static electric field to that of a particle because the field of a single charged particle is fixed in value and is static if that is what you wanted to know.
There is a difference between the electric field of a static charge and a moving charge. Again, I point to the Lienard Wiechert fields:
http://en.wikipedia.org/wiki/Liénar...onding_values_of_electric_and_magnetic_fields

In these equations the velocity as a fraction of the speed of light is given by ##\beta##. Thus, the case of a non-accelerating charge is given by ##\dot{\beta}=0## while the case of a stationary particle is given by ##\beta=0##. Even if you don't follow the meaning of the equation you can clearly see that it is a function of ##\beta## which means that the field depends on the velocity.
 
  • #33
Crazymechanic said:
there is no difference from a static electric field to that of a particle because the field of a single charged particle is fixed in value and is static if that is what you wanted to know.

Without even looking at the solution, this clearly cannot be true. Faraday's law and Gauss's law read ##\vec{\nabla} \cdot \vec{E} = 4\pi \rho## and ##\vec{\nabla} \times \vec{E} = -\frac{1}{c}\partial_t \vec{B}## so clearly the solution for an arbitrarily accelerating charge (time-varying delta function source) is in general different from the solution for the special case of a static charge, which simply has ##\vec{\nabla} \cdot \vec{E} = 4\pi Q\delta^3 (\vec{r} - \vec{r}')## and ##\vec{\nabla} \times \vec{E} = 0## where ##\vec{r}'## fixed.
 
  • #34
sorry wrong button .:)
 
Last edited:

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