= Rotating-frame magnetohydrodynamic momentum equation
{title2=$\rho D_t\mathbf u=-\nabla(P+B^2/(2\mu_0))+(\mathbf B\cdot\nabla)\mathbf B/\mu_0-\rho\nabla\Phi-2\rho\boldsymbol\Omega\times\mathbf u-\rho\boldsymbol\Omega\times(\boldsymbol\Omega\times\mathbf r)$}
For a rigid frame with constant <angular velocity> $\boldsymbol\Omega$, add the <Coriolis force> and <centrifugal force> to the inviscid <magnetohydrodynamic momentum equation>. A constant <magnetic permeability> and <solenoidal magnetic-field constraint> split the <Lorentz force density> into <magnetic pressure> and <magnetic tension>. This nonrelativistic conducting-fluid approximation neglects the <displacement current>, net electric-charge force and viscosity. <Differential rotation> belongs to the fluid's <velocity field>, not to a spatially varying rigid-frame rotation vector. A time-dependent frame requires the additional <Euler force>.
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