Spatio-temporal dynamics of a nanosecond pulsed microwave plasma ignited by time reversal

In the present paper, the first spatio temporal characterization of a time reversal microwave plasma generated in argon is provided using imaging. This novel source allows to ignite a plasma at a desired location in a reverberant cavity by focusing the electromagnetic energy in time and space. An important feature is the possibility to control the plasma position only by changing the input microwave waveform. The source is operated in a repetitive pulsed mode with very low duty cycle (typically 0.05%). Nanosecond pulses have rise time lower than one nanosecond. The generated plasmas have typical sizes in the millimeter range and are observed for dozens of nanoseconds. The plasma behavior is investigated for different pressures and repetition frequencies. A strong dependence is observed between each discharge pulse suggesting the existence of an important memory effect. The latter is probably due to argon metastable atoms and/or residual charges remaining in the post-discharge and allowing the next breakdown to occur at a moderate electric field

Space-Time Plasma-Steering Source: Control of Microwave Plasmas in Overmoded Cavities

Recently, space-time plasma-steering source has been proposed as an innovative microwave plasma source to meet the challenge of controlling plasmas in overmoded cavities. This concept has been successfully demonstrated experimentally, allowing the space-time control of nanosecond microwave plasmas on initiators. This paper gives insights into the path that shall be taken to reach full space-time control of plasmas in overmoded cavities. To that end, a key criterion, namely the “plasma-steering criterion,” is introduced and verified with a numerical model. This criterion must be respected for an accurate space-time control of plasmas in overmoded cavities. The usefulness of the plasma density (depending on its value with respect to the critical plasma density) on the plasma-control capabilities is also highlighted

Plasma generation using time reversal of microwaves

We report the experimental demonstration of plasma generation by time-reversal focusing. After a learning phase, the amplified time reversed signal built at a central frequency of 2.45 GHz injected in a low loss metallic cavity allows to ignite and maintain a localized centimer-sized plasma in argon at 133 Pa. The plasma spatial position is totally controlled by the signal waveform

Transient Electric Field Shaping With the Linear Combination of Configuration Field Method for Enhanced Spatial Control of Microwave Plasmas

The demonstration of enhanced spatial control of nanosecond microwave plasmas generated by the time reversal plasma source is presented in this paper. This new microwave plasma source relies on the spatio-temporal control of the electric field inside an all-metal plasma reactor by modifying the waveform of a high power microwave signal. More specifically, it originally used the spatio-temporal focusing capabilities of the time reversal method to focus a high electric field in a small location. However, a parasitic microwave breakdown can still occur at sharp corners or wedges inside the cavity due to the local enhancement of the residual electric field during time reversal focusing. Thus, it is proposed to use the linear combination of configuration field method to improve field control inside the reactor. Its transient electric field shaping capabilities turn out to be a good candidate for the development of a low pressure microwave ``plasma brush''

Formation de poudres dans des décharges d'acétylène en plasma micro-ondes multipolaire excité à la résonance cyclotronique électronique répartie (étude des nanocomposites carbone-carbone et leurs applications)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Plasma et son environnement. Plasmas Froids en France et au Québec

pour le champs 'auteurs', les Directeurs de publications apparaissent en premier puis le Directeur de collection.International audience15|Préface / Alix Gicquel.|19|Préface « France-Québec » / Alain Denoirjean.|23|Le Réseau « Plasmas Froids ».|33|Plasma-Québec, regroupement stratégique en science et applications des plasmas.|Plasma et son environnement.|47|1- Plasmas & liquides.|49|Phénomènes prédisruptifs dans les liquides : « modes » de propagation et mécanismes / Olivier Lesaint.|77|La gazéification de biomasse en ambiance plasma sur bain de verre / I. Carlesi, M. Mabrouk, C. Lafon, F.Lemont, J.M. Baronnet.|113|2- Plasmas & milieux poreux.|115|Décharges hors-équilibre à pression atmosphérique dans les milieux confinés, poreux ou alvéolaires / Pierre Tardiveau, Stéphane Pasquiers.|137|Transport / adsorption / diffusion / agrégation d’atomes pulvérisés par plasma dans les matériaux poreux. Expériences et modélisations / Pascal Brault, Jean-Marc Bauchire, Amaël Caillard, Anne-Lise Thomann, Sujuan Wu, François James, Christophe Josserand.|159|3- Plasmas & parois.|161|Pourquoi et comment est-ce que les parois des réacteurs contrôlent la chimie des plasmas basse pression ? / Gilles Cunge.|185|4- Sources & couplage sources - plasmas.|187|Plasma Micro-onde: Sources et techniques de couplage / François Silva, Khaled Hassouni.|229|Diagnostics électriques et alimentations des décharges / Nicolas Naudé, Jean Paillol, Antoine Belinger, Roland Subileau.|265|Matériaux piézoélectriques dédiés à la génération de plasmas froids : principes, applications et investigations récentes / François Pigache, Thierry Callegari.|293|5- Plasmas / surfaces.|295|Emission électronique sous impact d'électrons de basse énergie / Thomas Tondu, Mohammed Belhaj, Julien Roupie.|311|6- 1ère Journée Francophone.|313|Synthèse de films minces par condensation de vapeur réactive en régime de forte ionisation / Stephanos Konstantinidis, Rony Snyders.|329|Plasmas Froids en France et au Québec.|331|Plasmas d’entrée atmosphérique : problématique et enjeux / Arnaud Bultel, Julien Annaloro.|363|Les microdécharges / Rémi Dussart, Antoine Rousseau, Pascal Chabert, Vincent Puech, Leanne Pitchford, Nader Sadeghi, Thierry Belmonte, Caroline Boisse Laporte, Eric Robert.|407|Plasmas induits par laser pour la génération de photons « extrêmes » / Tsuneyuki Ozaki.|429|La Physique de l’interaction des impulsions laser relativistes avec la matière / Vladimir T. Tikhonchu

Signature of polycyclic aromatic hydrocarbons in very low-pressure helium plasmas

International audienc

PAHs as dust formation precursors in really-low pressure plasmas

International audienc

Cyclic evolution of the electron temperature and density in dusty low-pressure radio frequency plasmas with pulsed injection of hexamethyldisiloxane

International audienc