Blue jets and gigantic jets: transient luminous events between thunderstorm tops and the lower ionosphere

Abstract

An overview of general phenomenology and proposed physical mechanisms of large scale electrical discharges termed 'blue jets' and 'gigantic jets' observed at high altitude in the Earth's atmosphere above thunderstorms is presented. The primary emphasis is placed on summarizing available experimental data on the observed morphological features of upward jet discharges and on the discussion of recently advanced theories describing electrodynamic conditions, which facilitate escape of conventional lightning leaders from thundercloud tops and their upward propagation toward the ionosphere. It is argued that the filamentary plasma structures observed in blue jet and gigantic jet discharges are directly linked to the processes in streamer zones of lightning leaders, scaled by a significant reduction of air pressure at high altitudes.

Asymmetries in bidirectional leader development of lightning flashes

“…The minimum potential difference needed to sustain a positive streamer zone (in front of a leader tip) is about 3 times lower than for a negative streamer zone [e.g., Pasko, 2008] at equal air density. As regions of opposite charge in thunderstorms are often separated by a few kilometers vertically, air density differences can amplify differences in propagation thresholds and probably the degree of branching as well.…”

Lightning and middle atmospheric discharges in the atmosphere

“…Inspired by these early findings, two independent groups lead by Waltor Lyons of Mission Research Corporation (Lyons, 1994) and Davis Sentman of the University of Alaska, Fairbanks (Sentman and Wescott, 1993) initiated field programs to study the new phenomenon. The interest in TLEs have subsequently spurred worldwide and several hundred research papers and many review papers including books have been published (recent review papers- Pasko, 2008Pasko, , 2010Neubert et al, 2008;Sentman et al, 2008;Lyons et al, 2009;Raizer et al, 2010;Inan et al, 2010;Siingh et al, , 2012Pasko et al, 2012;Surkov and Hayakawa, 2012;Sato et al, 2015;Liu et al, 2015;etc.). Some features of TLEs are listed in Table 1.…”

“…Blue starters are slow moving fountains of blue light emanating from the cloud top and reaching up to $ 21 km altitude (Lyons et al, 2003a;Pasko, 2008). Edens (2011) reported a blue starter emanating from the cloud top at $15.2 km and terminating at 17 km altitude.…”

“…2. Blue starters (not shown in the figure), blue jets, gigantic jets are upward electrical discharges from top of thunderstorms with their tops reaching different altitudes: 20-30 km for blue starters, 40-50 km for blue jets, and 70-90 km for gigantic jets (Wescott et al, , 1996Pasko, 2003Pasko, , 2008Lyons et al, 2003a;Krehbiel et al, 2008;Siingh et al, 2012;Liu et al, 2015). Blue starters and jets are cone of light shooting upward from thunderstorm and their intensity decreases near their tops Edens, 2011;Chou et al, 2011;Liu et al, 2015).…”

“…Gigantic jets having a tree-like structure display complex dynamics (Su et al, 2003;Hsu et al, 2005;Chou et al, 2010;Soula et al, 2011;Liu et al, 2015). The top of gigantic jet may reach the Earth's lower ionosphere and can transfer charge between thunderstorm and ionosphere (Pasko, 2008). The amount of charge transfer will depend on the intensity and duration of gigantic jet.…”