AE005-11
TGF and elves produced by the same thunderstorm system
Wednesday, 9 December 2020: 16:31
Virtual
Nikolai Ostgaard1, Steven A Cummer2, Andrew Mezentsev1, Torsten Neubert3, Reglero Victor4, Martino Marisaldi5, Pavlo Kochkin1, David Sarria Sr1, Kjetil Ullaland1, Shiming Yang1, Georgi Genov1, Olivier Chanrion3, Freddy Christiansen3, Yunjiao Pu6, Alejandro Luque7 and Joseph R Dwyer8, (1)University of Bergen, Birkeland Centre for Space Science, Bergen, Norway, (2)Duke University, Electrical and Computer Engineering, Durham, NC, United States, (3)Technical University of Denmark, DTU Space, Kgs. Lyngby, Denmark, (4)University of Valencia, Image Processing Laboratory, Burjassot, Spain, (5)National Institute for Astrophysics, Bologna, Italy, (6)Duke University, Durham, United States, (7)Instituto de Astrofísica de Andalucía (IAA - CSIC), Granada, Spain, (8)University of New Hampshire, Department of Physics and Astronomy and the Space Science Center, Durham, NH, United States
Abstract:
On February 8, 2019 the Atmosphere-Space Interaction Monitor (ASIM) observed a TGF and an Elve from a positive Intra-Cloud (IC+) lightning
at the very beginning of a lightning flash north east of Puerto Rico. A second Elve produced by the return stroke (RS) of a negative Cloud-to-Ground (CG-) lightning was observed 456 ms later about 300 km south of the first one.
Radio measurements show that a short (30 us) and large (200 kA km) Energetic In-cloud Pulse (EIP) produced the electromagnetic wave for the first Elve while the RS of the CG- was the EM source for the second Elve. In both lightning weaker and slower currents followed.
Assuming that the EIP and the RS were the sources of the 777 nm emissions, both the delay relative to the UV pulse as well as the shape and duration of the 777 nm emissions can be explained by scattering and absorption inside the clouds.
The TGF produced by the IC+ lightning had the same duration as the EIP (~30 us), but due to +/-80 us timing uncertainty of the TGF we
can only state that TGF was produced simultaneous, just before (<60 us) or just after (<100 us) the EIP.
The source of the 777 nm emissions was most likely a current flowing in a hot channel, but we can not exclude the current from the TGF itself being the source.
