Simulations of electric field at the initiation altitudes of sprites and halos generated by the thundercloud charge structure and lightning channels of causative return strokes

0542839 - ÚFA 2022 DE eng A - Abstract
Kašpar, Petr - Kolmašová, Ivana - Santolík, Ondřej - Popek, Martin - Spurný, Pavel - Borovička, Jiří
Simulations of electric field at the initiation altitudes of sprites and halos generated by the thundercloud charge structure and lightning channels of causative return strokes.
EGU General Assembly 2021 (vEGU21: Gather Online). Göttingen: European Geosciences Union, 2021.
[EGU General Assembly Conference 2021. 19.04.2021-30.04.2021, online]
Institutional support: RVO:68378289 ; RVO:67985815
Keywords : sprites * halos * lightning strike * thunderstorm clouds * modeling of electric field
OECD category: Fluids and plasma physics (including surface physics); Astronomy (including astrophysics,space science) (ASU-R)
https://meetingorganizer.copernicus.org/EGU21/EGU21-8667.html

Sprites and halos are transient luminous events occurring above thunderclouds. They can be
observed simultaneously or they can also appear individually. Circumstances leading to initiation
of these events are still not completely understood. In order to clarify the role of lightning
channels of causative lightning return strokes and the corresponding thundercloud charge
structure, we have developed a new model of electric field amplitudes at halo/sprite altitudes. It
consists of electrostatic and inductive components of the electromagnetic field generated by the
lightning channel in free space at a height of 15 km. Above this altitude we solve Maxwell’s
equations self-consistently including the nonlinear effects of heating and ionization/attachment of
the electrons. At the same time, we investigate the role of a development of the thundercloud
charge structure and related induced charges above the thundercloud. We show how these
charges lead to the different distributions of the electric field at the initiation heights of the halos
and sprites. We adjust free parameters of the model using observations of halos and sprites at the
Nydek TLE observatory and using measurements of luminosity curves of the corresponding return
strokes measured by an array of fast photometers. The latter measurements are also used to set
the boundary conditions of the model.
Permanent Link: http://hdl.handle.net/11104/0320181