= Perpendicular magnetohydrodynamic shock
{title2=$B_2/B_1=\rho_2/\rho_1$}
For a planar <magnetohydrodynamic shock> with normal <velocity> and tangential <magnetic field>, <mass conservation> gives $\rho u=m$ and the <ideal magnetohydrodynamic induction equation> gives $uB$ constant across the front. Hence $B/\rho$ is unchanged, expressing <magnetic flux freezing>. Normal <momentum> flux is $\rho u^2+p+B^2/(2\mu_0)$, and energy flux per unit mass flux is $u^2/2+\gamma p/[(\gamma-1)\rho]+B^2/(\mu_0\rho)$, apart from a smooth common <gravitational potential>. The amplified tangential field contributes both <magnetic pressure> and <magnetic energy> transport.
Back to article page
