Does an electron beam bending lose energy by photon emission

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Discussion Overview

The discussion centers on the behavior of an electron beam in a magnetic field, particularly regarding energy loss due to photon emission as the beam bends. Participants explore classical physics concepts, the stability of electron beams, and the implications of electromagnetic radiation in various experimental setups.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • Some participants assert that an electron beam in a magnetic field radiates photons due to acceleration, leading to energy loss and potential spiraling inward.
  • Others argue that stable circular electron beams can exist without significant energy loss, suggesting that external energy compensates for any radiation emitted.
  • There is a discussion about the frequency of radiation produced by electron beams, with some clarifying that all electromagnetic radiation, not just visible light, is composed of photons.
  • Some participants question whether energy is measurable in laboratory setups using Helmholtz coils and if the current drawn by the coils changes when an electron beam is present.
  • Concerns are raised about the stability of electron beams in tabletop experiments, with some suggesting that energy loss is negligible at low velocities and low magnetic field strengths.
  • References to synchrotron radiation and Bremsstrahlung radiation are made, with participants discussing their relevance to energy loss in high-energy electron beams.
  • Some participants clarify misconceptions about the mechanisms of X-ray production and the conditions under which Bremsstrahlung occurs.
  • There is a contention regarding whether the original question implied the generation of electromagnetic frequency by the electron beam.
  • Several participants emphasize that if electrons are in a circular path, they must radiate energy due to acceleration, although the extent of this radiation and its implications remain debated.

Areas of Agreement / Disagreement

The discussion contains multiple competing views regarding the energy loss of electron beams in magnetic fields. Participants do not reach a consensus on the extent of energy loss or the mechanisms involved, indicating ongoing debate and uncertainty.

Contextual Notes

Participants express varying assumptions about the conditions under which electron beams operate, including velocity, magnetic field strength, and the nature of radiation emitted. The discussion highlights the complexity of the phenomena involved and the need for further clarification on specific experimental setups.

  • #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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