Alfvén wing

An Alfvén wing is a stationary Alfvénic disturbance attached to a conducting obstacle moving through a magnetized plasma. In a super-Alfvénic flow its boundaries follow downstream characteristics.

For a stationary cold-plasma disturbance with obstacle speed $u_0>u_A$, the characteristic slope is $m=\sqrt{u_0^2/u_A^2-1}$. It approaches $u_0/u_A$ in the strongly super-Alfvénic limit.