Mean-field electromotive force (source code)

= Mean-field electromotive force
{title2=$\boldsymbol{\mathcal E}=\langle\mathbf u\times\mathbf b\rangle$}

The mean-field electromotive force is the vector correlation $\boldsymbol{\mathcal E}=\langle\mathbf u\times\mathbf b\rangle$. Its <curl> enters the mean <resistive induction equation>. It is a local vector with units of velocity times magnetic field, not the scalar circuit voltage called <electromotive force>. A <space-time average of periodic modes> is often used to measure its transport coefficients.