Magnetic fields and superconductors

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Discussion Overview

The discussion revolves around the behavior of magnetic fields in relation to superconductors, specifically addressing the Meissner effect, the penetration of external magnetic fields, and the behavior of magnetic fields generated by superconducting currents. The scope includes theoretical and conceptual aspects of superconductivity.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions why external magnetic fields cannot penetrate a superconductor.
  • Another participant identifies the Meissner effect as a relevant phenomenon.
  • It is suggested that the magnetic field produced by the superconducting current does extend outside the superconductor.
  • A participant explains that superconductors are perfect diamagnets, creating an opposing magnetic field to repel external fields.
  • There is a mention that the superconducting effect is temperature-dependent, ceasing at higher temperatures.

Areas of Agreement / Disagreement

Participants present multiple viewpoints regarding the behavior of magnetic fields in superconductors, and the discussion remains unresolved with no clear consensus on all aspects.

Contextual Notes

Some limitations include the dependence on temperature for superconductivity and the need for more precise definitions regarding the behavior of magnetic fields in this context.

Forestman
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1. I have read that external magnetic fields cannot penetrate a superconductor. Why is this?

2. Does the magnetic field produced by the superconducting current extend outside of the superconductor? And if so, what happens when the magnetic field starts to collapse, can it renter the superconductor?
 
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1. The Meissner effect

2. Yes it does, if i remember correctly, but I let someone else answer with more precision ;)
 
Thanks malawi glenn
 
Just add a bit Mr malawi gleen explanation,,,

1. Superconductor is a perfect dia-magnetic. When you apply an external magnetic field it will create a magnetic field that oppose the external one so it's repel the magnet. The magnetic field still remain since the free electron continues moving even there's a collision, the energy lost extremely small.

2. Yes, until you give a heat to the superconductor or bring to the room temperature. cause superconductor effect only operate at very low temperature.
 

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