= Far-field P and S radiation from a point force
{title2=$A_P=n\cdot d,\quad \boldsymbol A_S=(I-nn^{\mathsf T})d$}
In a homogeneous <isotropic> solid, the far-field <P wave> is the radial projection of the force and the <S wave> is its transverse projection. For a unit force axis $d$, the magnitudes are $|\cos\theta|$ and $\sin\theta$. The approximation requires distance large compared with both reduced wavelengths; angular nodes can still be controlled by a smaller near-field contribution.
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