Radiation Modes in FRB 20220912A Microshots and a Crab PSR nanoshot

A microshot from FRB 20220912A \citep{H23} satisfies the uncertainty relation $\mathrm{\Delta }\omega \mathrm{\Delta }t\ge 1$ by a factor of only $⪅3$. A Crab pulsar nanoshot \citep{HE07} exceeds this bound by a similar factor. The number of orthogonal plasma modes contributing to the coherent radiation is also $\approx \mathrm{\Delta }\omega \mathrm{\Delta }t$, placing constraints on their excitation and growth.