Does an electron beam bending lose energy by photon emission

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In a vacuum, an electron beam subjected to an electric field can circle with a constant radius, but classical physics suggests that accelerating electrons emit photons, leading to energy loss. However, stable circular electron beams, such as those in particle accelerators, require continuous energy input to maintain their paths, counteracting any radiative losses. The discussion highlights that while low-energy electron beams may not exhibit significant energy loss, higher-energy scenarios, like synchrotron radiation, demonstrate measurable losses. Various participants clarify misconceptions about electromagnetic radiation and the conditions under which energy loss occurs in electron beams. Ultimately, the conversation emphasizes the importance of external energy sources to sustain stable electron paths in circular motion.
  • #31
houlahound said:
A non varying DC current in a wire would not emit EM but if the level changed then I expect it would.

A constant level DC current in a loop would not I expect emit EM but then I get tripped up because a circle motion implies acceleration and accelerating electrons radiate??

The device mentioned supplies a power to both the B field and the electrons, this power must compensate for radiative losses or the electrons would spiral out of a fixed radius...I'm so confused.

Did you read all the responses you were given? I could have sworn someone asked you to look up "synchrotron radiation". If you haven't, read this:

http://www.eecs.berkeley.edu/~attwood/srms/2007/Lec08.pdf

Pay attention to page 3, and see what happen for v<<c, and compare that to v~c.

Zz.
 
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  • #32
houlahound said:
A non varying DC current in a wire would not emit EM but if the level changed then I expect it would.

A constant level DC current in a loop would not I expect emit EM but then I get tripped up because a circle motion implies acceleration and accelerating electrons radiate??

The device mentioned supplies a power to both the B field and the electrons, this power must compensate for radiative losses or the electrons would spiral out of a fixed radius...I'm so confused.
I have the idea that a charged particle can be manipulated by electrostatic focusing and electromagnet lenses.
 
  • #33
I looked up synch, it seemed less relavent so I read up on cyclotron instead which seems totally relevant.

Will follow your link tho.
 
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  • #34
ZapperZ said:
Did you read all the responses you were given? I could have sworn someone asked you to look up "synchrotron radiation". If you haven't, read this:

http://www.eecs.berkeley.edu/~attwood/srms/2007/Lec08.pdf

Pay attention to page 3, and see what happen for v<<c, and compare that to v~c.

Zz.
I like the straight sections containing periodic magnetic structures to produce different effects.
 
  • #35
All I get from the link is "about blank"What I understand of synch is linear acceleration with undulations nothing close to circular motion at constant tangential velocity that I can figure.
 

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