Reflection of EM plane wave from a moving object

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SUMMARY

The discussion focuses on the reflection of electromagnetic (EM) plane waves from a perfectly conductive surface that is moving at a velocity comparable to the speed of light. It establishes that when treating the conductor as static and the wave source as moving, the primary consideration is the Doppler effect, which alters the observed frequency of the wave. To solve scattering problems involving moving scatterers, one must apply Lorentz transformations to transition between reference frames and utilize Maxwell's equations to calculate reflected fields. The discussion confirms that the frequency of the reflected wave increases due to the Doppler effect during both forward and backward propagation, while the amplitude remains unchanged.

PREREQUISITES
  • Understanding of Maxwell's equations
  • Familiarity with Doppler effect in wave mechanics
  • Knowledge of Lorentz transformations
  • Basic concepts of electromagnetic wave propagation
NEXT STEPS
  • Study the application of Lorentz transformations in electromagnetic theory
  • Learn about the Doppler effect in detail, particularly in the context of moving sources
  • Explore advanced scattering theory involving time-dependent media
  • Investigate numerical methods for solving Maxwell's equations in moving media
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Physicists, electrical engineers, and researchers in electromagnetic theory, particularly those interested in wave propagation and scattering in relativistic contexts.

sunjin09
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A plane wave normally incident onto a perfectly conductive surface moving in the normal direction with constant velocity comparable to the speed of light. How do I solve such problem? If I treat the conductor as static, and the source of plane wave as a moving source, do I only need to consider doppler effect, i.e., the wavelength or frequency of the plane wave is scaled, and the speed of light is unchanged?

In general, how to I solve a scattering problem with moving scatterers? Do I just treat them as time-dependent media and substitute into Maxwell's equations and figure out all the time-derivatives?
 
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Make a Lorentz transformation to the rest system of the conducting surface or moving object. Do the scattering calculation to find the reflected fields. Then LT these fields back to the original system.
 
Meir Achuz said:
Make a Lorentz transformation to the rest system of the conducting surface or moving object. Do the scattering calculation to find the reflected fields. Then LT these fields back to the original system.

Thank you for replying, since I don't know Lorentz transformation (or anything about relativity), let me elaborate what I have in mind:

Assuming I'm a person standing at the conducting surface measuring EM field fluctuations, if the source of the plane wave is moving toward me, I would observe an EM fluctuation at a frequency higher than the frequency of the wave observed in the original frame, but it is still a plane wave, that's all I as well as the conductor can tell, so I can solve for the reflected field just like what I normally do. Now I go back to the original frame, recalling the source of the reflected plane wave (surface currents) is moving toward me, all I can feel is a fluctuation at a higher frequency than the ALREADY INCREASED frequency when I did my calculation in the moving frame. Does this sound about right? The frequency increases two times as a result of the Doppler effect in both forward and backward propagation, and the amplitude is unchanged?
 

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