EM Field Angular Momentum Emission Without Emitting Energy?

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Discussion Overview

The discussion centers on the conditions under which electromagnetic (EM) angular momentum can be emitted into the vacuum of space without corresponding energy loss through radiation. Participants explore theoretical scenarios and implications related to this concept.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Kevin M. questions the conditions necessary for EM angular momentum to be emitted without energy loss, specifically referencing the behavior of the Poynting vector.
  • One participant describes a scenario involving a magnet and charged particles, suggesting that while angular momentum can be imparted to the EM field through torque, this process is more about absorption than emission.
  • Another participant expresses uncertainty, proposing that the idea of a photon possessing momentum without energy may not be feasible.
  • A further contribution references the Unruh effect, suggesting that it may have relevance to the discussion, particularly in the context of acceleration.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus, with multiple competing views and uncertainties regarding the feasibility of emitting angular momentum without energy loss.

Contextual Notes

Some assumptions regarding the nature of EM fields and the relationship between angular momentum and energy are not fully explored, and the implications of the Unruh effect remain unresolved in this context.

particlezoo
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To radiate energy, the Poynting vector must not drop faster than with the inverse square of the distance. Under what circumstances can EM angular momentum be emitted to the vacuum of space (i.e. without being recovered via inductive coupling) and yet not lead to energy losses through radiation? Is it possible?
Kevin M.
 
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Say there is a magnet. We bring charge from infinite distance and put it on magnet. Magnetic field give Lorentz force to the charge so we give torque to the field. Thus angular moment is put to electromagnetic field. This is an absorption not a emission but the reverse process, i.e. discharge from charged magnet might be of your interest. Best regards.
 
I am not sure at all here, but thinking in terms of photons, its like you want a photon to possesses momentum but not energy which simply is not possible.
 
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Hello

Well... I don't want to full your head with hot air (my mother-language is not English, I don't know if the idiom is correct), but you may take a look to this
https://en.wikipedia.org/wiki/Unruh_effect

Unruh derived the effect assuming linear acceleration; I think that it is still correct for centripetal.

Greetings.
 

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