An Etymological Dictionary of Astronomy and Astrophysics

Magnetohydrodynamics of a → plasma with very large (infinite) → conductivity. In this condition, → Ohm’s law reduces to E = -v × B, where E represents → electric field, B → magnetic field, and v the → fluid velocity.

Ideal MHD is the simplest model to describe the dynamics of plasmas immersed in a magnetic field. It is concerned with
→ one-fluid magnetohydrodynamics and neglects → resistivity. This theory treats the plasma composed of many charged particles with locally neutral charge as a continuous single → fluid. Ideal MHD does not provide information on the velocity distribution and neglects the physics relating to wave-particle interactions, as does the two-fluid theory as well. It does have the advantage that the macroscopic dynamics of the → magnetized plasma can be analyzed in realistic three-dimensional geometries (K. Nishikawa & M. Wakatani, 2000, Plasma Physics, Springer). See also → non-ideal magnetohydrodynamics.

See also: → ideal; → magnetohydrodynamics.