“…We have used a method of obtaining the dynamic equations which, in view of the nonrelativistic character of motions of a continuous medium and of the relativistic Maxwell equations, represents a combination of the variational principle in the form offered in [26,27] and of the requirement according to which the balance equation for the total energy-momentum tensor of a plasma-like medium and of the magnetic field should be satisfied. (Note that the requirement of satisfaction of the conservation laws, in particular, the energy balance equation, since the Landau pioneering work on the theory of superfluidity of helium II [50,51], is widely used to construct continuous models of quantum [37,[52][53][54] and classical [55][56][57] multivelocity continua.) The use of the base variational equation 2has allowed us to obtain a gauge-covariant system of the dynamic equations (129)-(131) and conditions at strong discontinuities (179)-(182).…”