On the Energy Source of Green Emissions in Ghost

Abstract The understanding on the formation mechanism of ghosts as a new category of transient luminous events and favorable conditions for their occurrence is limited. In this work, we examined six ground‐based observations of ghost events captured by digital SLR cameras. Notably, our data set contains the first ghost observation following a gigantic jet (GJ) featuring a diffusive top, with the altitudes of green emission spanning from 87 to 95 km and a duration of 333 ms. The ghost‐associated red sprite and GJ both contain a diffusive region with a large number of energetic electrons, indicating a common condition for ghost formation following various TLEs. Based on the calculated ratio between the blue and red emissions, the lowest reduced electric field ( E ‐field) responsible for the generation of ghost is inferred to be around 108 Td. Furthermore, the consecutive lightning strokes may contribute to the accumulation of ghost‐producing E ‐field.