= Magnetic field strength
{title2=$\mathbf H$}
In macroscopic <electromagnetism>, <magnetic field strength> is $\mathbf H=\mathbf B/\mu_0-\mathbf M$, where $\mathbf B$ is <magnetic flux density> and $\mathbf M$ is <magnetization>. In <SI> units $\mathbf H$ is measured in $\mathrm{A\,m^{-1}}$, while $\mathbf B$ is measured in <tesla (unit)> units. In a linear isotropic medium $\mathbf B=\mu\mathbf H$, where $\mu$ is <magnetic permeability>. The macroscopic <Ampère-Maxwell equation> writes its <curl> in terms of free current and <displacement current>. The electromagnetic <Poynting vector> is $\mathbf E\times\mathbf H$ in this convention.
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