Does a DC supplied superconductive coil give off radiation?

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SUMMARY

A DC supplied superconductive electric coil does not emit electromagnetic (EM) radiation, regardless of whether the current flows through superconducting or normal conducting materials. This conclusion is supported by Maxwell's laws and Gauss's Law, which indicate that static fields do not produce radiation. The discussion highlights that while individual electrons in circular motion can radiate, a continuous stream of electrons in a DC circuit results in a net cancellation of radiation due to the symmetry of the field. Additionally, quantum mechanical considerations further clarify that radiation does not occur in steady-state DC conditions.

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  • Understanding of Maxwell's laws of electromagnetism
  • Familiarity with Gauss's Law and its implications for magnetic fields
  • Knowledge of classical electrodynamics and the behavior of charged particles
  • Basic concepts of quantum mechanics as they relate to electron behavior in materials
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  • Study the implications of Gauss's Law in electromagnetic theory
  • Explore the Larmor Equation and its applications in radiation theory
  • Investigate the quantum mechanical treatment of electrons in conductive materials
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Physicists, electrical engineers, and students of electromagnetism seeking to understand the behavior of DC circuits and the conditions under which electromagnetic radiation is produced.

  • #31
vanhees71 said:
The drift velocity is more around ~1mm/s.
I read that drift velocity in superconductors is about 20 meters per second.
 
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  • #32
No.

For the third time, the A-level answer is radiation is caused by time-varying multipoles and these are zero for DC.
 
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  • #33
@hutchphd I think the cyclotron analogy is not usable here because in a coiled wire with steady current the actual electrons move slowly , very slowly so from the standpoint of a single electron the curled wire seems almost straight at the speed it is going. Much like we don't see and don't feel the curve we are actually making while traveling along a long road even though the Earth is curved and we are traveling along a curved path.

In cyclotrons on the other hand you have a relativistic electron beam being deflected by a perpendicular B field. But I have another example that i myself would like to ask, for steady DC current doesn't it also matter in what type of "conductor" the current is flowing? It seems to me a toroidal plasma does emit cyclotron radiation with a steady current, I suspect this has something to do with the confining fields which are present for a plasma and not present for a solid copper wire with DC.
 

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