Electromagnetic radiation in force field

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Discussion Overview

The discussion centers around the interaction of electromagnetic radiation, specifically laser light, with external force fields (electric and magnetic) in a theoretical context. Participants explore the implications of these interactions, particularly in terms of how the radiation behaves when passing through a region influenced by these fields, while neglecting gravitational effects.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions whether turning on a force field while radiation passes through would change the behavior of the radiation compared to its propagation in a vacuum.
  • Another participant suggests that unless the field strength is extremely high, such as near a magnetar, the field would have negligible effect on the radiation.
  • A participant proposes a scenario where electric fields might add together, questioning how the net electric field would affect the radiation.
  • Some participants express uncertainty about whether the electric fields would add and agree that the light itself would likely not be significantly affected.
  • There is a discussion about whether a field carries energy and if it should affect the curvature of space-time similarly to mass.
  • One participant asserts that the linearity of Maxwell's equations indicates no interactions between the electromagnetic fields would occur.
  • Another participant raises the possibility of minute curvature of space due to the energy of the field, questioning its significance.
  • There is a mention that electromagnetic radiation is not affected by electric fields, although gravitational fields may cause bending of light due to general relativity.
  • Some participants reiterate that a field must be accelerated for its energy to have an effect.

Areas of Agreement / Disagreement

Participants express differing views on the effects of electric and magnetic fields on electromagnetic radiation, with no consensus reached on whether the fields would interact or influence the radiation significantly. The discussion remains unresolved regarding the implications of energy carried by fields on space-time curvature.

Contextual Notes

Participants acknowledge the limitations of their assumptions, particularly regarding the strength of the fields and the conditions under which interactions might occur. The discussion also highlights the dependence on the definitions of terms like "effect" and "interaction."

danmay
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Say I were to shine a laser in a particular direction and quickly turn it off. After a certain time, the radiation passes through a region of space. Some force field (e.g. electric or magnetic; assume gravity is negligibly small) is then turned on as the radiation passes, such that no mass or charge ever interacts with the radiation, only the "field" does. Would it change the behavior of the radiation, say compared to its earlier propagation through vacuum?
 
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If I'm not mistaken, unless the strength of the field was unimaginably high, such as near a magnetar, the field would do effectively nothing.
 
Drakkith said:
If I'm not mistaken, unless the strength of the field was unimaginably high, such as near a magnetar, the field would do effectively nothing.

Would the electric fields add? Say the laser light E_rad varies from -5 to 5 Newton per coulomb. The applied E_app is a constant -10 Newton per coulomb. Then where the radiation passes, E_net varies from -15 to -5 Newton per coulomb.

I would think the magnetic field stays the same, since it varies with the time rate of change of the electric field, which is not altered by applying a constant electric field.
 
I'm not sure if it would add, but I'm fairly certain the light itself wouldn't be affected much, if at all.
 
Btw, doesn't a field carry energy? If so, shouldn't it affect the curvature of space-time like mass does?
 
The linearity of Maxwell's equations assures that no interactions between the two fields would occur.
 
Antiphon said:
The linearity of Maxwell's equations assures that no interactions between the two fields would occur.

Other than any minute curvature of space due to energy of the field? If that happens I mean.
 
Electromagnetic radiation like the laser light is not effected by electric field.
The laser light will bend slightly i.e deflect from its path in a strong gravitational field due to general relativistic effects.
 
danmay said:
Btw, doesn't a field carry energy? If so, shouldn't it affect the curvature of space-time like mass does?


yes danmay it will be effected by spacetime curvature.
 
  • #10
Drakkith said:
Other than any minute curvature of space due to energy of the field? If that happens I mean.

Antiphon said:
The linearity of Maxwell's equations assures that no interactions between the two fields would occur.

shreyakmath said:
yes danmay it will be effected by spacetime curvature.

On second thought I think a field has to be accelerated for any energy to come into play.
 

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