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Article
Magnetic field and current are zero inside ideal conductors
| Authors: |
Fiolhais, C. N., Essén, H., Providencia, C., Nordmark, A. |
| Document Type: |
Article |
| Pubstate: |
Published |
| Journal: |
Progress In Electromagnetics Research B |
| Volume: |
27
187-212 |
| Year: |
2011 |
AbstractWe prove a theorem on the magnetic energy minimum in a system of perfect, or ideal, conductors. It is analogous to Thomson's theorem on the equilibrium electric field and charge distribution in a system of conductors. We first prove Thomson's theorem using a variational principle. Our new theorem is then derived by similar methods. We find that magnetic energy is minimized when the current distribution is a surface current density with zero interior magnetic field; perfect conductors are perfectly diamagnetic. The results agree with currents in superconductors being confined near the surface. The theorem implies a generalized force that expels current and magnetic field from the interior of a conductor that loses its resistivity. Examples of solutions that obey the theorem are presented.
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