Does a DC supplied wavy superconductor give off EM radiation?

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Discussion Overview

The discussion centers on whether a superconductor supplied with direct current (DC) emits electromagnetic radiation. Participants explore the implications of the superconductor's shape and the nature of the current in relation to radiation emission, touching on theoretical and conceptual aspects.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant suggests that a superconductor flowing with direct current does not emit electromagnetic radiation, asserting that the shape of the loop is irrelevant and that DC does not produce radiation.
  • Another participant argues that when the current is initiated, a magnetic field is radiated due to the turn-on transient, and that a continuous DC maintains a stable magnetic field.
  • A different viewpoint mentions that there is radiation power due to accelerated charges, referencing an external post for further information.
  • One participant emphasizes that radiation is produced by a changing dipole moment or higher-order multipole, stating that a single accelerating charge does not produce radiation, and reiterates that a DC current has no changing moments, thus no radiation occurs.

Areas of Agreement / Disagreement

Participants express differing views on whether a DC supplied superconductor emits electromagnetic radiation, with no consensus reached. Some argue against radiation emission while others present conditions under which radiation might occur.

Contextual Notes

The discussion includes references to external posts and corrections made in previous threads, indicating that some claims may have been refined or contested over time.

binis
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A superconductor has the shape of a uniform plane wave. If it is flowed by a direct current,
is it emitting electromagnetic radiation or not?
 
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When the current is initiated, a magnetic field is radiated due to the turn-on transient.

A continuous direct current maintains a stable magnetic field, being the vector sum of all the magnetic fields from all the segments of the circuit.

When the current is terminated, the radiated magnetic field will fall back to zero.
 
binis said:
If it is flowed by a direct current,
is it emitting electromagnetic radiation or not?
No. The shape of the loop is irrelevant. When it is DC there is no radiation.

binis said:
have a look to this post
Have a look at the rest of that thread. The post you mention was subsequently corrected, and since you participated there you are already aware.

What produces radiation is a changing dipole moment (or higher-order multipole). A single accelerating charge does not produce radiation because of acceleration. It produces radiation because of a changing dipole moment.

A DC current has no changing moments, so no radiation, regardless of the shape of the loop.
 
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