Electric field inside a Superconductor

In summary, the conversation discussed the topic of superconductivity, specifically the property of having a zero electric field inside the material. This is deduced from the equation ##\mathbf j = \sigma \mathbf E## and the experimental evidence that ##\sigma \rightarrow \infty## for superconductors. The question was raised about the effect of an external time-varying electric field on this property, to which the response was that it may not be exactly zero but close enough for most purposes. The conversation concluded with a reference to Admiral Grace Hopper's statement about the speed of light and the importance of considering the size and frequency of the conductor.
  • #1
dRic2
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TL;DR Summary
Is electric field inside a superconductor always zero ?
I was reading chapter 3 of this book https://blackwells.co.uk/bookshop/product/Superconductivity-by-James-Arnett/9780198507567, which is a brief introduction to superconductivity. It is stated that inside a superconductor the Electric filed is always zero. This is deduced from the equation ##\mathbf j = \sigma \mathbf E## and taking as an experimental evidence that ##\sigma \rightarrow \infty## for a superconductor (page 51).

What if I apply an external time-varying electric field ? Is ##\mathbf E## still zero ? It would be like the electrons instantaneously move to adapt to the new field... Is is possible ?
 
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  • #2
Not exactly, but way close enough for most things. Speed of light.
Never forget Admiral Grace Hopper's admonition the a foot corresponds to a nanosecond so unless your conductor is large or frequency high no worries
 
  • #3
Thanks, just wanted to be sure because the author refers to this property various times in the next pages to prove stuff.
 

FAQ: Electric field inside a Superconductor

1. What is a superconductor?

A superconductor is a material that has zero electrical resistance and can conduct electricity without any loss of energy. This phenomenon occurs when the material is cooled below a certain critical temperature.

2. How does the electric field behave inside a superconductor?

The electric field inside a superconductor is zero. This is because the material has no electrical resistance, so any electric field that is applied to it is completely canceled out.

3. Why does the electric field disappear in a superconductor?

The disappearance of the electric field in a superconductor is due to the Meissner effect. When the material is cooled below its critical temperature, it expels any magnetic fields within it, which in turn cancels out any electric fields.

4. Can an electric field be created inside a superconductor?

Yes, an electric field can be created inside a superconductor by applying an external magnetic field. This will cause the superconductor to lose its zero resistance and allow for the flow of electricity.

5. What are the practical applications of the electric field inside a superconductor?

The zero resistance and disappearance of electric fields in superconductors make them ideal for use in power transmission, MRI machines, and particle accelerators. They also have potential applications in quantum computing and levitation technology.

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