Covariant form of the ideal magnetohydrodynamic "connection theorem" in   a relativistic plasma
  The magnetic connection theorem of ideal Magnetohydrodynamics by Newcomb [Newcomb W.A., Ann. Phys., 3, 347 (1958)] and its covariant formulation are rederived and reinterpreted in terms of a "time resetting" projection that accounts for the loss of simultaneity in different reference frames between spatially separated events. 
F. Pegoraro
physics.plasm-ph