A5058459661- Lightning and Electromagnetic Phenomena
- Vacuum and Plasma Arcs
- High voltage insulation and dielectric phenomena
- Electrical Fault Detection and Protection
- Combustion and Detonation Processes
- Fire effects on ecosystems
- Aerosol Filtration and Electrostatic Precipitation
- Plasma Diagnostics and Applications
- Laser Design and Applications
- Laser-induced spectroscopy and plasma
- Radiation Effects in Electronics
- Ocular and Laser Science Research
- Power Transformer Diagnostics and Insulation
- Electrostatic Discharge in Electronics
- Earthquake Detection and Analysis
- Advancements in Semiconductor Devices and Circuit Design
- Integrated Circuits and Semiconductor Failure Analysis
- Fire Detection and Safety Systems
- Welding Techniques and Residual Stresses
- Ionosphere and magnetosphere dynamics
- Semiconductor materials and devices
- Diamond and Carbon-based Materials Research
- Electrical Contact Performance and Analysis
- Icing and De-icing Technologies
- Thermal Analysis in Power Transmission
Université Paris-Saclay
2016-2024
Office National d'Études et de Recherches Aérospatiales
2005-2024
Laboratoire d'Étude des Microstructures
2012
Advanced Research Projects Agency - Energy
2008
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
1988-2003
CEA DAM Île-de-France
1988-2003
Centre d'études de l'emploi
1995
Analyses of electric and magnetic fields measured at distances from tens to hundreds meters the ground strike point triggered lightning Camp Blanding, Florida, 10 20 m Fort McClellan, Alabama, in conjunction with currents channel base optical observations, allow us make new inferences on several aspects discharge additionally verify recently published “two‐wave” mechanism M component. At very close ranges (a few or less) time rate change final portion dart leader field can be comparable that...
This paper presents a new modelling of positive-discharge development, based on simplifying assumptions. It these assumptions, which are deduced from the existing theoretical models and concern mainly coupling between leader corona region. model has been validated through comparison simulations with experimental results in reference configuration rod - plane gap subjected to various positive impulse voltages. also used simulate discharge behaviour perturbations applied potential form.
The triggering and guiding of leader discharges using a plasma channel created by sub-joule ultrashort laser pulse have been studied in megavolt large-scale electrode configuration (3–7 m rod-plane air gap). By focusing the close to positive rod it has possible, with 400 mJ pulse, trigger guide leaders over distances 3 m, lower inception voltage 50%, increase velocity factor 10. dynamics breakdown without analyzed means streak camera electric field current probes. Numerical simulations...
This paper presents current and electric field measurements from two triggered lightning flashes, 9519 9516, initiated by the “classical” “altitude” technique, respectively, at Camp Blanding, Florida, in 1995. The measurement for flash shows that upward positive leader, top of grounded wire unreeled triggering rocket, propagates a discontinuous pattern made successive pulses tens to few hundreds amperes separated intervals 20–25 μs. downward negative leader electrically floating conductor,...
A silicon-on-insulator (SOI) technology with a hardened variant is presented, focusing on some of the weak points that could impede progress SOI toward production high-speed VLSI. The devices described here use LOCOS isolation method instead commonly used MESA and thin active silicon layer which no epitaxy takes place. Dose dose rate tests were performed both technologies various circuits special-purpose devices. An analysis sensitivity to single-event upset, (SEU) was made, hardness...
This paper is devoted to the study of unsteady electric arcs and effects electrodes on their dynamics. One objectives simulate understand three-dimensional behaviour in complex geometries, which create important fluctuations column reattachments electrodes. The usual methods solve problem arc–electrodes coupling are not suitable arcs. We propose a numerical development both steady-state without additional assumptions. method based incorporation into computational domain. It validated with...
Abstract The aim of this paper is to investigate radiative properties thermal air plasmas in wide ranges pressure and temperature, analyse the accuracy some spectral geometrical approximations high-pressure transfer applications. Comprehensive calculations absorption spectra, including molecular, atomic ionic line continuum radiation, are presented dependence these spectra on level analysed. high resolution association with a rigorous ray-tracing method, then used study P 1 simplified SP 3...
In this paper, we present the investigation realized on an experimental setup that simulates arc column subjected to transient phase of a lightning current waveform in laboratory conditions. Optical emission spectroscopy is employed assess space- and time-resolved properties high pulsed arc. Different peak levels are utilised work, ranging from 10 kA 100 kA, with time around 15 µs. Ionic lines nitrogen oxygen used determine radial profiles temperature electron density channel over 2 µs 36 A...
During a lightning strike to an aircraft in flight, the channel becomes deformed airflow and displaced along aircraft, so-called swept stroke. The deformation displacement are caused by interaction between aerodynamic flow plasma properties of together with surface. main part current is continuous magnitude hundreds amperes duration milliseconds. objective this article analyse during phase order parametrize them; parametrization used companion paper (Larsson et al J. Phys. D: Appl. 33...
A scheme for computer simulation of a negative stepped leader is developed, based on physical description the processes occurring during step development. The applied to three‐dimensional model interaction between downward and grounded mast under two assumptions, one with without an upward positive initiated from tip mast. modeling performed 2‐m 10‐m‐diameter leaders −10‐MV −40‐MV electrical potential, respectively. reacts only at final jump‐over, irrespective emission mast, thus suggesting...
A specific experiment has been designed to study the simultaneous development of two leaders opposite polarities from a floating electrode suspended in plane-to-plane gap. In paper, physical properties both discharges are investigated detail, and quantitative analysis inception thresholds, corona charges, velocities, etc. is presented. Special attention devoted mechanisms negative discharge, including processes 'pilot system' 'space leader', already observed previous experiments...
Using a plasma channel produced by an ultrashort laser pulse, we have studied the triggering and guiding of positive leader from tip 2-m vertical rod standing on bottom plane 7-m plane-plane gap. The purpose this setup was to reproduce in laboratory electric field conditions leading onset upward ground as downward negative is approaching during thunderstorm, order demonstrate working principle possible future lightning rod. properties laser-created been function synchronization pulse with...
In this paper, we present the laboratory study on three experimental setups that produce a free arc channel subjected to transient phase of lightning current waveform. This work extends high-current pulsed characterization performed in previous studies for peak levels up 100 kA. Eleven waveforms with value ranging from 100--250 kA different growth rates and action integrals are studied, allowing comparison test benches. These correspond standard ones used aircraft certification processes....
High current pulsed arcs are of significant industrial interest and, aiming to reduce time and cost, there is progressively more need for computation tools that describe predict the behaviour these arcs. These simulation codes inputs validations by experimental databases, but accurate data missing this category electric discharges. The principal lack understanding with respect transient phase current, which can reach thousands amperes in a few microseconds. In paper, we present work realized...
In-flight experiments have shown that in most cases the aircraft striking process is initiated by bidirectional propagation of two leaders opposite polarities. A laboratory experiment has been designed to analyse detail development such a 'bi-leader' from an electrically floating conductor suspended 10.5 m plane-to-plane gap, submitted impulse voltage. The shape object, electrode configuration and voltage waveshape optimised allow observation simultaneous both discharges before their...
We have used the Bondio-Gallimberti model of positive leader propagation to simulate laboratory experiments laser triggering and guiding upward leaders initiated from a ground rod. The proves be capable reproducing all important features laser-guided that been observed experimentally. effect laser-created plasma channel is taken into account in by adjusting value charge per unit length leader, which has measured lower for than an ordinary one. related critical temperature at air transition...