VHF discharges in storm cells producing microbursts

An experiment was carried out in which 3-D mapping of VHF sources was compared to a 3-D description of the reflectivity and dynamics of associated cloud cells observed by a radar network. Data from 61 microbursts were analyzed and it was found that, in 93 pct. of the cases, electrical activity precedes outflow development. The results confirm that the peak in intracloud activity precedes the maximum value of the outflow

Propagation and Structure of Planar Streamer Fronts

Streamers often constitute the first stage of dielectric breakdown in strong electric fields: a nonlinear ionization wave transforms a non-ionized medium into a weakly ionized nonequilibrium plasma. New understanding of this old phenomenon can be gained through modern concepts of (interfacial) pattern formation. As a first step towards an effective interface description, we determine the front width, solve the selection problem for planar fronts and calculate their properties. Our results are in good agreement with many features of recent three-dimensional numerical simulations. In the present long paper, you find the physics of the model and the interfacial approach further explained. As a first ingredient of this approach, we here analyze planar fronts, their profile and velocity. We encounter a selection problem, recall some knowledge about such problems and apply it to planar streamer fronts. We make analytical predictions on the selected front profile and velocity and confirm them numerically. (abbreviated abstract)Comment: 23 pages, revtex, 14 ps file

Theoretical modelling of the laboratory negative stepped leader

Communication to : 1994 International aerospace and ground conference on lightning and static electricity, Mannheim (Germany), May 24-27, 1996SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : 22419, issue : a.1996 n.128 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

VHF discharges in storm cells producing microbursts

Tire de : ICOLSE 1991, Cocoa Beach, FL (USA), April 16-19, 1991SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : 22419, issue : a.1991 n.57 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc