Magnetohydrodynamics equations

Magnetohydrodynamics (MHD) is a branch of physics and engineering that investigates the effects of a magnetic field on the motion of an electrically conducting fluid. The term ‘magnetohydrodynamics’ and its acronym MHD may be somewhat misleading, it is often used to designate physical phenomena in which the conducting fluid is not a liquid, but rather a compressible ionized gas or a plasma. Same authors prefer more specific terms as magneto-fluid-dynamics or magneto-gas-dynamics. Since the pioneering experiment of Michael Faraday in 1832, MHD has appeared as an appealing way to manipulate a fluid without the intervention of mechanical means. Faraday failed his attempt to measure the electric current produced by the MHD interaction taking place in the water of the river Thames flowing through the Earth’s magnetic field. However, his experimental activities opened the way to the study of a mechanism which has fundamental implications in plasma physics, astrophysics, and engineering. The MHD interaction principles have been proposed for a number of technological applications. A first example can be found in MHD generators, in which the MHD interaction is used for the direct conversion of the working fluid energy into electrical energy. MHD generators have been intensively investigated as a means to increase the efficiency of electrical power plants and as a viable alternative to gas turbines. MHD electric generators has also been proposed in nuclear-powered spacecraft for deep space missions.