Reflection of EM plane wave from a moving object

AI Thread Summary
A plane wave incident on a moving perfectly conductive surface requires careful consideration of the Doppler effect and Lorentz transformations for accurate analysis. Treating the conductor as static while considering the source as moving simplifies the initial calculations, focusing on frequency changes due to the Doppler effect. To solve the scattering problem, one should apply Maxwell's equations in a time-dependent medium framework, making necessary Lorentz transformations to account for the motion of the scatterer. The reflected fields can then be calculated and transformed back to the original frame for final analysis. This approach confirms that the frequency observed will be higher due to the Doppler effect, while the amplitude remains unchanged.
sunjin09
Messages
310
Reaction score
0
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?
 
Science news on Phys.org
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?
 
Thread 'A quartet of epi-illumination methods'
Well, it took almost 20 years (!!!), but I finally obtained a set of epi-phase microscope objectives (Zeiss). The principles of epi-phase contrast is nearly identical to transillumination phase contrast, but the phase ring is a 1/8 wave retarder rather than a 1/4 wave retarder (because with epi-illumination, the light passes through the ring twice). This method was popular only for a very short period of time before epi-DIC (differential interference contrast) became widely available. So...
I am currently undertaking a research internship where I am modelling the heating of silicon wafers with a 515 nm femtosecond laser. In order to increase the absorption of the laser into the oxide layer on top of the wafer it was suggested we use gold nanoparticles. I was tasked with modelling the optical properties of a 5nm gold nanoparticle, in particular the absorption cross section, using COMSOL Multiphysics. My model seems to be getting correct values for the absorption coefficient and...
Back
Top