HR: 11:32h
AN: AE12A-05    [Abstracts]
TI: Laboratory characterization of the current produced by a negative leader during a step
AU: * Lalande, P
EM: lalande@onera.fr
AF: ONERA, 29 Avenue de la division Leclerc, chatillon, 92320 France
AU: L'helgoualc'h, I
EM: helgoual@onera.fr
AF: ONERA, 29 Avenue de la division Leclerc, chatillon, 92320 France
AU: Broc, A
EM: alain.broc@onera.fr
AF: ONERA, 29 Avenue de la division Leclerc, chatillon, 92320 France
AU: Blanchet, P
EM: blanchet@onera.fr
AF: ONERA, 29 Avenue de la division Leclerc, chatillon, 92320 France
AU: Laroche, P
EM: laroche@onera.fr
AF: ONERA, 29 Avenue de la division Leclerc, chatillon, 92320 France
AU: Andre, C
EM: christophe.andre@dga.defense.gouv.fr
AF: CEAT, 47 Route de Saint Jean, Balma, 31130 France
AU: Tamin, L
EM: laurent.tamin@@dga.defense.gouv.fr
AF: CEAT, 47 Route de Saint Jean, Balma, 31130 France
AU: Campo, c
EM: claude.campo@@dga.defense.gouv.fr
AF: CEAT, 47 Route de Saint Jean, Balma, 31130 France
AB: In the last decades, several ground systems have been developed to detect and locate the total lightning activity for meteorological investigations and thunderstorm nowcasting. These systems detect the VHF-UHF pulses produced by the negative stepped leader which is one of the main components of electromagnetic radiation of lightning. The large VHF-UHF radiation of the negative leader is due to its stepped propagation during which strong and fast pulses of current are produced. In April 2005, a laboratory experiment was performed at the lightning test center of CEAT on negative leader in order to characterize the current pulse associated with the stepped propagation. The electrode arrangement was composed of an electrode with a conic tip, from 4 to 6 m above the ground. A negative switching voltage of 3 MV was applied to the electrode to produce the negative leader. The measurements were composed of a fast current measurement (DC-500 Mhz) at the electrode tip, electric field at ground, UHF-VHF measurement and photomultipliers. An image converter and still cameras have been also used to characterize the development of the negative leader. From the measurements obtained during this campaign, the relationships between geometric parameters of the discharge and the current during a step are discussed.
DE: 3324 Lightning
SC: Atmospheric and Space Electricity [AE]
MN: Fall Meeting 2005