What Perytons Aren't, and Might Be

Understand

Chirped radio pulses known as perytons are consistent with plasma propagation, but an astronomical origin has been excluded.

• TE and TM waveguide modes have dispersion relations formally similar to those of plasmas, and emission at the plasma frequency of a plasma recombining by two-particle processes also produces a chirp $\delta t \propto \omega^{-2}$, but these hypotheses fail quantitatively.
• The chirp might be approximately fitted to three-body recombination, cyclotron radiation in exponentially decaying fields, or to the resonance of a distributed LC circuit whose component conductors move, but no specific source has been identified.