Current Concentrated Along Axis

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SUMMARY

The discussion centers on the behavior of electric current in a fat wire, specifically addressing why current does not concentrate solely along the wire's axis despite the attraction between parallel wires. Griffiths raises the question of potential electric repulsion among conduction particles, prompting further inquiry into the underlying physics. Dave contributes by referencing the relationship between current density (j), conductivity (σ), and electric field (E), noting that a curl in E contradicts established principles, as curl E equals zero.

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  • Understanding of electric current and its behavior in conductors
  • Familiarity with Maxwell's equations, particularly the curl operator
  • Knowledge of electric field concepts and their mathematical representations
  • Basic principles of electromagnetism and particle interactions
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  • Study Griffiths' "Introduction to Electrodynamics" for foundational concepts
  • Explore the implications of curl in electromagnetic fields using vector calculus
  • Research the behavior of current density in various conductor geometries
  • Investigate electric field transformations in different reference frames
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Physics students, electrical engineers, and anyone interested in advanced electromagnetism and the behavior of electric currents in conductors.

ResonantW
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Griffiths brings up a point that it might make sense that current in a fat wire would want to concentrate itself mainly along the axis of the wire, given that parallel wires attract each other.

He then asks us to figure out why this might not happen, but to be honest I would think it should! The only thing I can think of is some sort of electric repulsion in the conduction particles' rest frame, but I feel like there are more subtle points in transforming the frames like this. Where am I going wrong?
 
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hi there :)

who is Griffiths and do you have a link to his study ?

Dave
 
That would give j a curl. Since j=\sigma E, that would give E a curl, but curl E=0.
 

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