  Relativistic runaway electron avalanches (RREAs) imply a large multiplication
of high energy electrons (~1 MeV). Two factors are necessary for this
phenomenon: a high electric field sustained over a large distance and an
energetic particle to serve as a seed. The former sustains particle energies as
they keep colliding and lose energy randomly, and the latter serves as a
multiplication starting point that promotes avalanches. RREA is usually
connected to both terrestrial gamma-ray flashes (TGFs) and gamma-ray glows
(also known as Thunderstorm Ground Enhancement (TGE) when detected at ground
level) as possible generation mechanism of both events, but the current
knowledge does not provide a clear relationship between these events (TGF and
TGE), beyond their possible common source mechanism, still as they have
different characteristics. In particular, their timescales differ by several
orders of magnitude. This work shows that chain reactions by TGF byproducts can
continue for the timescale of gamma-ray glows and even provide energetic
particles as seeds for RREAs of gamma-ray glows.
