A representation of toroidal MHD in terms of stream functions and potentials

An exact representation of toroidal magneto-hydrodynamics is proposed, in which the electromagnetic and the velocity fields are represented in terms of stream functions and potentials, without assuming any spatial symmetries. Two important features of this representation are the use of a time-independent but otherwise arbitrary reference field B0, and the fact that the vector product of the velocity V with B0, and not V itself, is represented in terms of stream functions. In this way the equations take a form which allows relatively easy physical interpretation and is well suited for deriving reduced MHD equations for particular stability problems. (author)