30 research outputs found
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