Answers are grounded in this paper and cite their sources.
The first time-resolved spectrum of a return stroke between the cloud and ground has been obtained with a slitless spectrograph. The time for luminosity to rise from zero to its peak in a section of the channel is 10 micro-seconds or less, and the intense emission lines are attributed to singly ionized nitrogen atoms. Several faint lines persisting for approximately 150 microseconds are due to neutral nitrogen and oxygen atoms.
No takes yet. Share an insight, caveat, or question.
Richard E. Orville (1966) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: