The Naked Scientists

The Naked Scientists Forum

Author Topic: Are superconductors perfect micro/radio wave mirrors?  (Read 1334 times)

Offline ScientificSorcerer

  • Sr. Member
  • ****
  • Posts: 367
  • Thanked: 2 times
    • View Profile



My question is pretty simple, are superconductors perfect mirrors for radio waves and microwaves?  you see these kinds of waves go right through regular mirrors and don't really reflect off of reflective surfaces like normal light does.  Radio/microwaves tend to reflect off of conductive surfaces  like copper and aluminum plates.  But some energy is absorbed by the conductive material do to it's resistance and turns into heat. regular mirrors also absorb some light because normal mirrors are not perfectly reflective.

But superconductors are perfectly conductive and thus should be perfectly reflective to very low frequency electromagnetic radiation.  Can you see why I think this? It seems pretty straight forward but I tried to google this question and didn't find much to confirm or deny this possibility.

But if indeed it is perfectly reflective then you could imagine the possibility of a microwave capacitor which might have huge energy storage capabilities.  heck you might have to come up with a new unit of measurement to identify this kind of energy storage. A new form of measurement similar to Farads but with electromagnetic radiation.  don't ask me why but I would name this new measurement  Bakers  ;)


 

Offline evan_au

  • Neilep Level Member
  • ******
  • Posts: 4106
  • Thanked: 245 times
    • View Profile
Re: Are superconductors perfect micro/radio wave mirrors?
« Reply #1 on: 26/05/2015 20:52:50 »
Superconductors only operate up to a threshold frequency, usually in the microwave part of the spectrum.

The extremely low losses of superconducting mirrors is used in RF resonators for particle accelerators. But the expensive liquid helium refrigeration limits it to extreme applications with extreme budgets.

At optical and infra-red wavelengths, light has enough energy to split the Cooper pairs that support superconductivity. This effect is used in extremely sensitive Single-Photon Detectors.

As for storing huge amounts of energy, you are looking at the amount of electromagnetic energy that can be packed into a vacuum. The vacuum itself has a very high energy density (Joules per kg), but the Joules per Litre is not so good. If you add in the surrounding superconductors and refrigerators, it looks a lot less attractive.

The same volume of water would store far more thermal energy, and filling that volume with a high-surface area conductor+dielectric would result in a capacitor with very high energy storage density. Filling the same volume with petrol would store even more chemical energy.
« Last Edit: 26/05/2015 21:07:43 by evan_au »
 

Offline syhprum

  • Neilep Level Member
  • ******
  • Posts: 3817
  • Thanked: 19 times
    • View Profile
Re: Are superconductors perfect micro/radio wave mirrors?
« Reply #2 on: 06/06/2015 11:29:45 »
I am surprised at the comment that a vacuum stores a large number of Joules per Kilogram presumably the vacuum has zero mass so that J/Kg must be infinite
 

The Naked Scientists Forum

Re: Are superconductors perfect micro/radio wave mirrors?
« Reply #2 on: 06/06/2015 11:29:45 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums