Branch of The study of the interaction between a magnetic field and plasma treated as a continuous medium. Most of the universe contains not normal gas, but instead plasma. Many dynamical astronomical processes are caused by the subtle nonlinear relationship between a magnetic field and plasma. There is virtually no interaction with concerned with self-excitation of magnetic fields in any large rotating mass of electrically conducting fluid in motion (usually turbulent) such as liquid metals. Self-exciting dynamo action is believed to account for magnetic fields at the planetary, stellar, and galactic scales.
Some or all content above used with permission from J. H. Wittke.