Alfvén surface
= Alfvén surface
{wiki=Alfvén_surface}
The Alfvén surface is a concept in plasma physics, particularly in the context of magnetohydrodynamics (MHD) and astrophysical plasmas. It represents a boundary within a plasma where the influence of magnetic fields on plasma dynamics undergoes a significant transition. In more detail, the Alfvén surface is defined as the locus of points in space where the Alfvén speed equals the local speed of the plasma.