# Thomson Scattering -- elastic collisions conundrum

• I
• C-Science
In summary, the Thomson scattering effect is described as the changing electric field of an accelerating electron which carries energy that radiates out in all directions. However, it is observed that the energy of detected photons is not lower in wavelength as expected, indicating that the energy is not evenly spread out in all directions. Further investigation is suggested, using the classical approach and Maxwell's equations to understand electromagnetic radiation.
C-Science
Teacher described the Thomson scattering effect through the lens of the electric field changing as a moving particle is accelerated. The changing electric field of the electron accelerating carries with it an amount of energy, and this energy radiates out from the acceleration event. (there were more details but thats the gist I got)

I'm ok with this.

but since the electric field radiates out in all directions, the energy of the Efield shift should be spread out in all directions (this is where I think my thought process might be wrong, but I dont understand why) And if the energy is spread out, the energy of detected photons released along the wave front should be lowered by a factor of the angle of the detector - this would yield an elastic collision, but detected photons would be lower in wavelength. BUT detected photons are the same wavelength for Thomson scattering.. so it seems as all the energy of the collision is not released over a spherical surface, but in a specific direction, which denies the energy spreading out from the acceleration event in all directions of the E field. help?

I would say that a) there are no photons in classical EM (photons are part of the QM theory of light); and, b) generally you need to look at Maxwell's equations to understand EM radiation.

Klystron, vanhees71 and tech99
C-Science said:
but since the electric field radiates out in all directions, the energy of the Efield shift should be spread out in all directions
This doesn't necessarily have to follow. Best to do what @PeroK suggests and use the classical approach (there's nothing naughty about that!)

Klystron

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