Poynting vector - uniform vs accelerated charge

  • #1
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Main Question or Discussion Point

I am trying to understand why an accelerating charge emits radiation/electromagnetic waves but a uniformly moving one does not. I saw one video on Youtube where it seemed that it was explained by the fact that with a uniformly moving charge the Poynting vector was pointing 'in to the volume' - no energy was flowing out - but that with an accelerating charge the Poynting vector was pointing 'out of the volume' hence there was energy out that would be detected as electromagnetic waves. Is that the gist of it?
 

Answers and Replies

  • #2
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For a uniformly moving charge there is an inertial frame of reference in which the charge is not moving and does not radiate. For an accelerated charge there is no inertial frame of reference in which the charge is stationary.. However there is more to the story; for an accelerated charge, radiation is only detected if the detector is not accelerating with the charge. You might want to look at the thread at https://www.physicsforums.com/threads/paradox-electron-radiates-in-a-gravitational-field.950608/page-2#post-6020694

The mentors and forum staff were most patient with my questions in that thread.
 

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