Electromagnetic wave; the classical model

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Discussion Overview

The discussion revolves around the classical model of electromagnetic waves, specifically addressing the nature of fields and their propagation. Participants explore the relationship between static fields and dynamic waves, as well as the implications of Maxwell's equations.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions how fields can travel as waves, suggesting that fields permeate space and weaken with distance.
  • Another participant cites Maxwell's equations to assert that electromagnetic waves are dynamic and can propagate through space.
  • A different viewpoint states that fields do not travel; rather, they oscillate at fixed points as the wave passes by.
  • Some participants clarify that while fields and waves are different concepts, plane waves can propagate without weakening in a lossless medium.
  • There is a suggestion that the wave creates electric and magnetic fields in front of itself, indicating a process of propagation rather than movement.

Areas of Agreement / Disagreement

Participants express differing views on the nature of electromagnetic waves and fields, with no consensus reached on the fundamental question of how fields can be said to travel as waves.

Contextual Notes

Some claims rely on specific interpretations of electromagnetic theory and may depend on definitions of terms like "field" and "wave." The discussion includes various assumptions about the nature of propagation and the characteristics of different types of waves.

Cheman
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Electromagnetic wave; the classical model...

There appears to me to be an obvious flaw in the classical version of electro magnetic waves (before we even consider quantum theory. :rolleyes: ) Forgive me if I'm wrong but surely fields cannot travel as waves - after all, a field permeates space, getting weaker with distance, so how exactly can these fields actually travel forward as a wave?

Thanks in advance. :smile:
 
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Maxwell's equations say they can. A static field permeates space and gets weaker with distance, yes, but electromagnetic waves are not static fields, they are dynamic (vary with time).

Claude.
 
The fields don't travel. At any position in space, the field (either electric or magnetic) simply oscillates as the wave goes past. A wave is just an excitation of the local electromagnetic field.
 
Fields and waves are different concept, but I supposed you're talking about optical field here? Then yeah, optical field from a point source, for instance, gets weaker with distance. But for field propagation in the form of plane wave, it doesn't get weaken as long as the medium is not lossy.
 
OldTee said:
Fields and waves are different concept, but I supposed you're talking about optical field here? Then yeah, optical field from a point source, for instance, gets weaker with distance. But for field propagation in the form of plane wave, it doesn't get weaken as long as the medium is not lossy.

Optic is just a particular cases of Electromagnetic .. so the thing you said appky to eletromagnetic too
 
the wave isn't "moving" its creating an electric and magnetic field infront of it self, its not moving its propagating, a change in electric field creates the magnetic field in front of it which is also changing, and then electric field is created in front of that...and so on..
 

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