Classical perfect diamagnetism: expulsion of current from the plasma interior.
The vanishing of generalized helicity is shown to be the necessary and sufficient condition for a perfect conductor to display perfect diamagnetism, considered to be the defining attribute of a conventional superconductor. Although conventional superconductivity is brought about by quantum correlations in classical systems, prepared in the state of zero initial helicity (helicity is a constant of the motion for a perfect conductor), it can mimic the superconductor's behavior.
Mahajan
S M
SM
Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712, USA.