Segnalazione di 2 articoli su Gigantic Jet (2004 e 2005) scaricabili da internet

Simulation of gigantic jets propagating from the top of thunderclouds to the ionosphere
Lizhu Tong, Kenichi Nanbu, and Hiroshi Fukunishi
Earth Planets Space, 57, 613–617, 2005
http://www.terrapub.co.jp/journals/EPS/pdf/2005/5707/57070613.pdf

ABSTRACT
A randomly stepped leader propagation model is developed to study gigantic jets, a new type of lightning, connecting thunderclouds to the ionosphere. The thundercloud is considered as one electrode igniting gigantic jets and the ionosphere is assumed as the other. The propagation of stepped leader is considered as a field controlled random growth process. The electric field is produced due to the thundercloud charges and the selfconsistently propagating leader. A leader propagation probability is proposed to determine whether the leader grows at the next step and what the step direction of the leader is in case of growth. The results show that leader propagation spans ～72 km from igniting position to the ionosphere. The simulation of leader propagation appears to be in agreement with the structure of observed gigantic jets.

Numerical analysis of initiation of gigantic jets connecting thunderclouds to the ionosphere
Lizhu Tong, Kenichi Nanbu, and Hiroshi Fukunishi
Earth Planets Space, 56, 1059–1065, 2004
http://www.terrapub.co.jp/journals/EPS/pdf/2004/5611/56111059.pdf

ABSTRACT
The initiation of giant electrical discharges called as “gigantic jets” connecting thunderclouds to the ionosphere is investigated by numerical simulation method in this paper. Using similarity relations, the triggering conditions of streamer formation in laboratory situations are extended to form a criterion of initiation of gigantic jets. The energy source causing a gigantic jet is considered due to the quasi-electrostatic field generated by thunderclouds.
The quasi-electrostatic field is assumed to be axisymmetrical. We calculate the electric fields for different thundercloud charges. The electron dynamics from ionization threshold to streamer initiation are simulated by the Monte Carlo technique. It is found that gigantic jets are initiated at a height of ～18–24 km. This is in agreement with the observations. The distributions of electron positions and electron energies at different initiation heights are presented. The method presented in this paper could be also applied to the analysis of the initiation of other discharges such as blue jets and red sprites.

Questi mi mancavano! Grazie, Renzo.