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Abstract We examined three observations of green emission events (labeled as event A, B and C, respectively) associated with red sprites as captured by amateurs. In all cases, the green emissions were recorded atop of red sprite. Based on the location of causative strokes and background star fields for events A and B, their altitudes are confined between 88 and 100 km, with the maximum brightness at 90.7 and 95.5 km, respectively. Events B and C were lit up for a second time after the recurrence of a sprite element, extending their duration to approximately 1,084 ms and 732.6 ms, much longer than that (about 500 ms) for event A; the intensity of green emissions was also enhanced due to sprite recurrence. It is inferred that the recurrence of sprite elements could affect the ambient condition by further increasing electron density and strengthening the electric field for the ghost production. 

Abstract Terrestrial Gamma‐ray Flashes (TGFs) are ten‐to‐hundreds of microsecond bursts of gamma‐rays produced when electrons in strong electric fields in thunderclouds are accelerated to relativistic energies. Space instruments have observed TGFs with source photon brightness down to ∼10¹⁷–10¹⁶. Based on space and aircraft observations, TGFs have been considered rare phenomena produced in association with very few lightning discharges. Space observations associated with lightning ground observations in the radio band have indicated that there exists a population of dimmer TGFs. Here we show observations of TGFs from aircraft altitude that were not detected by a space instrument viewing the same area. The TGFs were found through Monte Carlo modeling to be associated with 10¹⁵–10¹²photons at source, which is several orders of magnitude below what can be seen from space. Our results suggest that there exists a significant population of TGFs that are too weak to be observed from space.