Proposed experimental test of an alternative electrodynamic theory of superconductors

•A new experimental test of electric screening in superconductors is proposed.•The electric screening length is predicted to be much larger than in normal metals.•The reason this was not seen in earlier experiments is explained.•This is not predicted by the conventional BCS theory of superconductivity.

An alternative form of London’s electrodynamic theory of superconductors predicts that the electrostatic screening length is the same as the magnetic penetration depth. We argue that experiments performed to date do not rule out this alternative formulation and propose an experiment to test it. Experimental evidence in its favor would have fundamental implications for the understanding of superconductivity.