Observations by the LOFAR radio telescope of a fast negative leader propagation mode
- 1University of Groningen, Kapteyn Astronomical Institute, physics, Groningen, Netherlands (o.scholten@rug.nl)
- *A full list of authors appears at the end of the abstract
We report on recent observations made by the LOFAR radio-telescope of a fast propagation mode in negative leaders we named Rapid Negative Leader (RNL).
The RNL has a variety of properties that make them clearly distinct from negative leaders or dart leaders, such as -- fast propagation, -- emission of strong broad-band pulses, -- emission of very high VHF power, -- a reduced density of located sources, and -- terminating with the spawning of a large number of negative leaders in a small area. RNLs are almost always observed in the initial stage of a lightning flash, but may also occur much later. They may occur repeatedly in a certain part of the cloud.
We interpret a RNL as negative leader developing in strong electric field due to a relatively small highly-charged cloud, probably created by a local turbulence, with a typical size of order 5 km2. The strong field will lead to a larger than usual charge at the leader tip resulting in an increased propagation velocity as well as a strongly enhanced emission of VHF power.
Since for the initiation of a lightning flash strong ambient electric fields are required, it is thus no surprise that the initial leader is in fact a RNL.
O.Scholten, B.M.Hare, J.Dwyer, N.Liu, C.Sterpka, I.Kolmatsova, O.Santol, R.Lan, L.Uhlir, S.Buiting, A.Corstanje, H.Falcke, T.Huege, J.R.H.Hoerandel, G.K.Krampah, P.Mitra, K.Mulrey, A.Nelles, H.Pandya, J.P.Rachen, T.N.G.Trinh, S.terVeen, S.Thoudam, T.Winchen
How to cite: Scholten, O. and the LOFAR Lightning and Cosmic ray group: Observations by the LOFAR radio telescope of a fast negative leader propagation mode, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10876, https://doi.org/10.5194/egusphere-egu21-10876, 2021.
