Effects of a discovery of the monopole

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Discussion Overview

The discussion revolves around the nature of magnetic fields, specifically whether they are conservative or non-conservative, and how the existence of magnetic monopoles might influence this classification. Participants explore theoretical concepts related to vector fields, curl, and potential functions.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question whether magnetic fields are conservative, noting that the presence of curved paths suggests non-conservativeness, while textbooks often classify them as conservative.
  • One participant emphasizes that the classification of a field as conservative can be determined by calculating the curl of the field, indicating that a zero curl implies a conservative field.
  • Another participant introduces the concept of path independence of line integrals and the existence of a scalar potential, linking these ideas to the operation of curl and Poincare's Lemma.
  • There is a suggestion to analyze a specific example involving a potential vortex to illustrate these concepts further.
  • One participant asserts that if the curl of a magnetic field is non-zero, it indicates that the field is path-dependent and thus not conservative.

Areas of Agreement / Disagreement

Participants express differing views on the classification of magnetic fields as conservative or non-conservative. While some agree on the method of using curl to determine conservativeness, there is no consensus on the implications of these findings or the role of monopoles in changing this classification.

Contextual Notes

Limitations in the discussion include the dependence on definitions of conservative fields, the assumptions made about the nature of magnetic monopoles, and the unresolved mathematical steps related to curl and vector potentials.

Somali_Physicist
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I guess i have two questions , is the magnetic field conservative or non-conservative.As far as i can see just looking at a magnetic field we have a curved path hence it wouldn't be conservative, however many textbooks assume it is.Is there something I am not seeing here?

Furthermore would monopoles change the category such a field sits in.
 
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Somali_Physicist said:
I guess i have two questions , is the magnetic field conservative or non-conservative.As far as i can see just looking at a magnetic field we have a curved path hence it wouldn't be conservative, however many textbooks assume it is.Is there something I am not seeing here?

This is not a question that is open for debate, or something that you can judge simply by "looking". There IS a clear and direct TEST of any field for it to be "conservative". Find the curl of this field. Then ask yourself : "What does it mean if the curl of this field is zero, and what does it mean if the curl of this field is not zero?"

Furthermore would monopoles change the category such a field sits in.

One step at a time. Do the first one first.

Zz.
 
Well, after you've read about

-path independence of line integrals over vector fields
-existence of a scalar potential of a vector field and this path independence
-local version: or in other words, what this has to do with the operation curl
-and what Poincare's Lemma tells you

go ahead with a nice mind-boggling example, the potential vortex
$$\vec{V}(\vec{x}) = \frac{1}{x_1^2+x_2^2} \begin{pmatrix} -x_2 \\ x_1 \\0 \end{pmatrix}$$
and calculate ##\text{curl} \vec{V}## and then the line integral along an arbitrary circle parallel to the ##x_1##-##x_2##-plane with center on the ##x_3## axis. Hint: cylinder coordinates can in this case be both a good idea and adding even more to the confusion, but it's really a good kind of confusion.
 
ZapperZ said:
This is not a question that is open for debate, or something that you can judge simply by "looking". There IS a clear and direct TEST of any field for it to be "conservative". Find the curl of this field. Then ask yourself : "What does it mean if the curl of this field is zero, and what does it mean if the curl of this field is not zero?"
One step at a time. Do the first one first.
[
Zz.
Curl of a field is zero implies that there is no circulation .It also means that such a vector is a gradient of some scalar potential. I guess you could also see along a closed curve you would always have zero work done.As you have to apply same work to get to a point.Wikipedia defines it as something that only depends on position not path taken.

Ok so for a magnetic field:
∫B.dl = μ0∫J.dA
by stokes theorem:
∫(∇xB).da = ∫μ0J.dA
therefore:
∇xB = μ0J
∇xB =0 only if J = 0

If the curl of a vector field isn't zero than it is path dependent and hence not a gradient of a scalar potential.That would imply its not zero, so not a conservative vector field?
 

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