Accelerating Current: Does Bending a Wire Produce EM Radiation?

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    Accelerating Current
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Discussion Overview

The discussion revolves around the question of whether bending a wire produces electromagnetic (EM) radiation due to the acceleration of charges within the wire. It explores concepts related to current flow, charge acceleration, and the conditions under which radiation is produced, touching on both theoretical and conceptual aspects.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant asserts that bending a wire causes the charges (current) to accelerate, suggesting that this should lead to radiation.
  • Another participant counters that radiation is produced only by changing currents or charge distributions, claiming that a steady current does not produce radiation, even in a circular configuration.
  • A participant introduces the concept of synchrotron radiation, noting that charged particles in circular paths, such as those in accelerators, do produce radiation, which raises questions about the behavior of electrons in a bent wire.
  • There is confusion expressed regarding the comparison between steady currents in curved paths and electrons in synchrotrons, questioning why the former does not radiate like the latter.
  • One participant explains that a steady current in a circular wire maintains a constant charge density, leading to zero or constant electric fields and magnetic fields, which do not result in radiation, contrasting this with the time-dependent fields associated with electrons in accelerators.

Areas of Agreement / Disagreement

Participants express differing views on whether bending a wire produces EM radiation, with some arguing for the possibility based on charge acceleration and others maintaining that steady currents do not radiate. The discussion remains unresolved, with confusion and uncertainty evident among participants.

Contextual Notes

Participants reference Maxwell's equations and the conditions under which radiation occurs, but there are unresolved assumptions regarding the definitions of steady versus changing currents and the implications of charge density in different scenarios.

SandeshPhy
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Current is simply flow of charge,
and acceleration of charged particles produces EM radiation.
Then if we bend a wire,charges(current) would be accelerated as they change direction,then a bent wire must radiate.Is it true?
 
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Radiation is produced by a changing current, or a changing charge distribution. A steady current does not produce radiation, even in a circular wire.
 
When charged particles, electrons, protons etc, are traveling in circular paths in accelerators they produce radiation sometimes know as synchrotron radiation.
Some synchrotrons are used as sources of X-rays.
 
technician said:
When charged particles, electrons, protons etc, are traveling in circular paths in accelerators they produce radiation sometimes know as synchrotron radiation.
Some synchrotrons are used as sources of X-rays.

But then even steady current moving in curved path is same as electrons moving in synchrotons.the electrons do radiate so why doesn't the current(which is simply flow of electrons)?

I am totally confused here?
 
A steady current in a circular wire has a constant charge density throughout. Maxwell's equations gives zero/constant electric field (if the wire is approx. zero charge or charged) and constant magnetic field - no radiation. An electron in a cyclotron does NOT have a constant charge density so the electric field is time dependent. For that matter the magnetic field would be more complicated too!

The way I understood the first post I imagined bending a wire as charge was flowing through it - in this case there would be radiation of course, since the magnetic field would change.
 

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