Help visualizing E-field between moving magnets

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    E-field Magnets
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Discussion Overview

The discussion revolves around visualizing the electric field generated between two moving bar magnets, particularly focusing on the effects of their motion and orientation. Participants explore the implications of changing magnetic fields on electric fields, including scenarios where the magnets attract or repel each other, and the potential for electrical breakdown in related experiments.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning
  • Experimental/applied

Main Points Raised

  • One participant seeks to understand the electric field gradient induced by two horizontal bar magnets moving towards each other at constant velocity, questioning the visual representation of this phenomenon.
  • Another participant suggests that the orientation of the magnets' poles (N and S) is crucial for understanding their interaction, raising the question of whether they are attracting or repelling each other.
  • A participant expresses interest in the scenario where the magnets are attracting each other, indicating a preference for this case in the discussion.
  • One suggestion involves drawing a 2-D representation of the magnetic field between attracting magnets and considering how to mathematically model the fields for visualization.
  • A participant proposes using the Lorentz transform to derive the fields for moving magnets, indicating a mathematical approach to the problem.
  • Another participant shares their interest in conducting example problems and calculations to understand the magnitudes of the fields, linking their inquiry to an experiment with a generator and questioning the conditions under which electrical breakdown might occur due to induced electric fields.

Areas of Agreement / Disagreement

Participants express varying levels of interest in different scenarios (attracting vs. repelling magnets) and approaches (visualization vs. mathematical modeling). There is no consensus on the specific outcomes or methods to visualize the electric field, and multiple viewpoints remain regarding the implications of the changing magnetic fields.

Contextual Notes

Participants have not fully resolved the assumptions regarding the orientation and motion of the magnets, nor have they established the mathematical relationships necessary for complete understanding. The discussion includes speculative elements about the conditions for electrical breakdown, which remain unverified.

Who May Find This Useful

This discussion may be of interest to students and enthusiasts of electricity and magnetism, particularly those exploring the interactions between moving magnetic fields and induced electric fields, as well as those conducting related experimental investigations.

ArchieDave
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I'm doing my best at learning electricity & magnetism for the first time and I could use some help. Let's say I have two horizontal bar magnets moving horizontally towards each other at constant velocity. The changing B field should induce an electric field gradient in the perpendicular direction, but I can't quite figure out what this would look like. And what happens when the magnets stop and reverse direction?

to make things more complicated, what if I turn the magnets at 90 degrees relative to their motion. Does this double the E field? Any help (or references to go to) is appreciated.
 
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To figure this out, I think we'd have to know how the N and S poles of the two magnets are oriented relative to each other. As we push the two magnets together, are they repelling or attracting each other?
 
I'm actually curious about both cases but let's just say they are attracting each other.
 
For visualizing, we can start by drawing (in 2-D) the magnetic field between two attracing magnets. (e.g. as show in http://en.wikipedia.org/wiki/Force_between_magnets). Do this in one position and another position where they are a little closer.

I don't know how much math you want to use in this. One could develop the equations for the fields and then plot a representation.
 
ArchieDave said:
I'm doing my best at learning electricity & magnetism for the first time and I could use some help. Let's say I have two horizontal bar magnets moving horizontally towards each other at constant velocity.
The easiest way to do this will be to write down the field for the magnet at rest and then use the Lorentz transform to calculate the field for the moving magnet.
 
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Thanks for the direction. I'm wanting to do some example problems and calculations to get a feel for the magnitudes of the fields relative to a source I'm familiar with. What got me interested in this was an experiment with a generator with no load connected. It seems to me that if dB/dt was large enough the resulting electric field could cause electrical breakdown in the motor. Does this happen? My thought was to check this myself by seeing what what value of B or what velocity would be needed to cause kV level fields. Does this make sense?
 

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