Understanding Reflection and Ion Movement in EM Waves

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Discussion Overview

The discussion centers on the concepts of reflection and ion movement in electromagnetic (EM) waves, particularly in relation to skin depth in conductors and the behavior of light in water. It explores theoretical aspects and implications of these phenomena.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the nature of reflection in conductors, suggesting that since skin depth indicates wave attenuation, the reflected wave may not be the incident wave.
  • Another participant explains that the incident wave causes electrons in a conductor to oscillate, radiating waves that can interfere with the incident wave, leading to reflection.
  • Concerns are raised about the ability of large ions in water to respond to high-frequency light, with a participant questioning whether these ions can move at the same frequency as the wave.
  • A participant notes that water has too few free electrons to radiate under the influence of an incident wave, yet reflection still occurs from the water volume.
  • There is a discussion about why waves do not radiate from every boundary, with one participant suggesting that waves can be decomposed into point sources that radiate in all directions, but the total wave may not radiate isotropically.

Areas of Agreement / Disagreement

Participants express differing views on the nature of reflection and the behavior of ions in response to EM waves. The discussion does not reach a consensus on these points, indicating ongoing uncertainty and exploration of the topic.

Contextual Notes

Participants reference concepts such as skin depth, electron oscillation, and the behavior of ions, but there are unresolved assumptions regarding the mechanisms of reflection and the conditions under which these phenomena occur.

Thierry12
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1. Since skin depth is the attenuation of the wave in a conductor, this means the reflection isen't the incident wave... so what is the reflection?

2. Water doesn't stop light since it's frequency is too high, i saw on forum it's because the big ions can't move fast enought. How can that be? Wont they move as the same frequency as the wave?

Ty
 
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Thierry12 said:
1. Since skin depth is the attenuation of the wave in a conductor, this means the reflection isen't the incident wave... so what is the reflection?

2. Water doesn't stop light since it's frequency is too high, i saw on forum it's because the big ions can't move fast enought. How can that be? Wont they move as the same frequency as the wave?

Ty

The incident wave penetrates deeper than the skin layer. It makes the electrons oscillate and radiate in all directions. The waves radiated in the incident wave direction add with the incident wave. The thicker layer, the more intense the radiated wave. It happens it has the opposite sign amplitude. So the radiated and incident waves gradually cancel when you go inside.

The waves radiated with the electrons in the opposite direction are called the "reflected" waves.

In water there too few free electrons to radiate under the incident wave influence. Yet the same phenomenon takes place, so you have reflection from the water volume too.

Bob.
 
thanks a lot!
 
Can someone tell me why waves arent coming out of every borders since it radiates in all directions?
 
The total wave does not radiate in every direction though. You can decompose any wave into being the result of a summation of point sources. These point sources radiate in all directions using a spherical wave. But the sum total of all these sources is not guaranteed to radiate isotropically.

Either way though, for the most part there is generally some reflection of waves off of all surfaces.
 
thanks a lot for the help again!
 

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