Published online by Cambridge University Press: 14 August 2015
A preliminary account is presented of some characteristics of Fast Fine Structure, that is fine structure with time scales in the milli second range, and of the flare events in which they appear. Fast Fine Structure is found to be a fairly common phenomenon that could, but not necessarily does, appear in flare events of any importance occurring at any longitude. It may occur with any type of microwave burst (except most likely “Rise” and “Fall”). It appears more often in the more important events and it may last for only a few seconds up to many minutes. Fast Fine Structure may have any degree of circular polarization, apparently independent of its longitude position.