Longitudinal magnetic forces in conductors

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Discussion Overview

The discussion centers on understanding longitudinal magnetic forces in conductors within the frameworks of classical electrodynamics and quantum electrodynamics (QED). Participants explore the phenomena that lead to these forces, particularly in the context of experiments that demonstrate the ability of these forces to break wires under sufficient current, excluding effects like melting or pinch effects.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant queries whether there is a straightforward explanation for longitudinal forces in conductors within classical electrodynamics or QED.
  • Another participant suggests that the issue may relate to a potentially missing term in Maxwell's laws, referencing older and more recent papers that could provide insights.
  • A different participant notes that longitudinal forces might be explained using the Maxwell stress tensor and seeks clarification on this approach.
  • One participant challenges the interpretations of Graneau's experiments, asserting that the current geometry in those experiments does not support the claims made, as the current is not moving longitudinally.

Areas of Agreement / Disagreement

Participants express differing views on the interpretation of experiments and the applicability of existing theories, indicating that multiple competing perspectives remain without a consensus on the explanations for longitudinal forces in conductors.

Contextual Notes

Some discussions reference specific papers and interpretations that may not be universally accepted, highlighting the complexity and ongoing debate surrounding the topic.

TrickyDicky
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Is there a simple way to understand within classical electrodynamics (or QED) the experiments that show longitudinal forces in conductors that are capable of breaking wires when enough current is conducted and are not due to melting or pinch effect?
 
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I think that this relates to an old issue about a possibly missing term in Maxwell's laws, based on experiments with such things as rail guns.
You can find a rather old paper about it in the Journal of Applied Physics:
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5114236&abstractAccess=no&userType=inst

I see that this links to a more recent paper by Moyssides, which I had not seen and may give sufficient answer:
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=1211177&navigation=1
 
Only the first paper seems to be directly related to the OP, anyway I haven't subscriptiom.
I read somewhere these longitudinal forces could be accounted for using the Maxwell stress tensor and I was wondering if anyone knew how.
 
Graneau has misinterpreted his experiments. I looked in detail at his papers some years ago. In each case, the geometry has current moving in a non-longitudinal direction. He considered this negligible but it isn't.
 

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