Dynamo theory

Summary

Dynamo theory studies how the motion of an electrically conducting fluid can create and maintain a magnetic field against its decay by electrical resistance. It explains the magnetic fields of the Earth, the Sun, other planets and stars, and galaxies. Its basic mathematical problem is the kinematic dynamo problem: for which velocity fields does the induction equation of magnetohydrodynamics have solutions that do not decay? Antidynamo theorems, such as Cowling's theorem, show that flows or fields with too much symmetry cannot work.