= Radiation pattern
{title2=$dP/d\Omega$}
A radiation pattern specifies emitted <power> per <solid angle> as a function of direction. For a slowly moving point <electric charge> with <acceleration> $\mathbf a$, $dP/d\Omega=q^2|\mathbf n\times\mathbf a|^2/(16\pi^2\epsilon_0c^3)$. Its <integral> over directions is the <Larmor formula>; its fore-aft symmetry implies zero net radiated <three-momentum> in the instantaneous rest <inertial frame>. Directional detector <power> includes the distinction between source emission time and arrival time.
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