Mesure directe de poussée sur un propulseur de type arc sous vide

International audienceThis paper presents the experimental characterization of a vacuum arc thruster on a thrust balance. A prototype of the Plasma Jet Pack (PJP) thruster, with an energy of 2.04 J/pulse, has been installed on ONERA micronewton thrust balance. Measurements of the thrust have been performed at different pulse repetition frequencies. The mean thrust value is between 57 μN (at 2 Hz) and 288 μN (at 10 Hz). The impulse bit has been measured on 120 single discharges. The mean Ibit is 29.2 μN.s, in line with the value inferred from mean thrust measurements

Caractérisation expérimentale des performances d'un propulseur de Hall 50W

International audienceThe performance metrics and the plume characteristics of a miniaturised Hall thruster are investigated. The thruster is part of the ExoMG-nano propulsion platform developed by Exotrail and, during the test campaign, it is operated with a power processing unit prototype. Beam divergence, ion energy distribution, thrust and specic impulse are the primary parameters measured during the investigation. The thrust is directly measured with a pendulum-type thrust balance, while the ion current density and ion energy distribution are measured using electrostatic probes. At about 53W of total input power and at a total xenon flow rate of 2.7 sccm (anode plus cathode), the thrust, total specific impulse and total effciency are 2 mN, 800 s and 15%, respectively. At the same power, the mass utilisation effciency is about 67 %, the divergence effciency is 70-75% and the half-angle where 90% of the plume ion current is found is 68-72o. A comparison with other commercially available propulsion platforms is also presented

Finite Element Analysis of Ring-Shaped Emission Profile in Plasma Bullet

Using a one-way coupled model of neutral gas flow and plasma dynamics we report a mechanism to explain the ring-shaped emission pattern that has been observed experimentally in plasma bullets at atmospheric pressure. We solve a fluid model with the local field approximation in one-dimensional cylindrical coordinates, corresponding to a cross-section of a plasma bullet. Pulselike uniform electric field is assumed to be applied perpendicular to the simulation domain. Time and spatially resolved spectroscopic measurements support the simulation results

Investigation on the ion velocity distribution in the magnetic nozzle of an ECR plasma thruster using LIF measurements

Proceeding of: 35th International Electric Propulsion Conference (IEPC), October 8-12, Atlanta, Georgia, USALaser-induced fluorescence (LIF) is a non-intrusive technique that can provide useful information on ion production and acceleration in electric propulsion system. In this paper, spatially resolved LIF measurements of Xe+ are performed in the plume of an electron cyclotron resonance plasma thruster. The mapping of ion velocity distribution function in the magnetic nozzle shows that the ions are accelerated over a distance greater than 12 cm. A mean axial velocity up to 16 km/s has been obtained at 1 sccm and 26 W. The acceleration of ions is compared for different xenon flowrates.This work was made in the framework of project MINOTOR that has received funding from the European Union’s Horizon H2020 research and innovation programme under grant No 730028

Measurement of anisotropic plasma properties along the magnetic nozzle expansion of an electron cyclotron resonance thruster

Proceeding of: 35th International Electric Propulsion Conference (IEPC), October 8-12 2017, Atlanta, Georgia, USAThis work presents experimental measurements along the magnetized plume of the ECR thruster developed by ONERA. Langmuir probes are used to determine the electron energy probability function (eepf) at different axial positions, revealing the non-local character of the distributions. The second part of the paper details a combined diagnostics of non-intrusive diamagnetic loop measurements and laser induced fluorescence to estimate the perpendicular electron temperature inside the plasma source. Averaged perpendicular electron pressure, plasma density, ion velocity at the exit plane and perpendicular electron temperature are determined as functions of the mass flow rate.This work was made in the framework of project MINOTOR that has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 730028

Ion acceleration in the magnetic nozzle of an ECR thruster: comparison of experimental measurements with a quasi 1D kinetic model

Proceeding of: Space Propulsion Conference, SP 2018,14-18 mayo, SevillaThis paper presents experimental results on the magnetic nozzle of the 50 W Electron Cyclotron Resonance (ECR) thruster of ONERA, consisting of a 27 mm diameter ECR cavity and a fully divergent magnetic nozzle, created by a Neodymium permanent magnet. The diagnostics installed are a cylindrical Langmuir probe to measure plasma potential, plasma density and electron temperature, and a Laser Induced Fluorescence set-up to measure the mean ion kinetic energy. Both the ion velocity and plasma potential profiles seem to be independent of the mass flow rate when normalized with the electron temperature estimated at the sonic transition of the plasma flow. This sonic transition appears to be slightly shifted downwards of the thruster exit. Results are compared with a supersonic collisionless kinetic 1D model where electron dynamics account for magnetic mirror effects and potential barriers, while ions are treated as a fluid cold species.This work was made in the framework of project MINOTOR that has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 730028. This work was additionally supported by the Spanish R D National Plan (Grant No. ESP2013-41052-P)

The "MINOTOR" H2020 project for ECR thruster development

Electric propulsion has been identified by European actors as a strategic technology for improving competitiveness in different space areas such as in-space operations and transportation. The European Commission has set up the "In-space Electrical Propulsion and Station-Keeping" Strategic Research Cluster (SRC) in the "Horizon 2020" funding framework with the goal of enabling major advances in Electric Propulsion for in-space operations and transportation. In this framework, the MINOTOR project was funded to mature a potentially disruptive cathodeless electric propulsion technology, the Electron Cyclotron Resonance (ECR) thruster. In recent years, the consortium leader ONERA has built up a large experience on ECR technology for electric propulsion, and the MINOTOR project will bring the expertise from three industrial partners (TMI, TAS-B and SAFRAN) and two university partners (UC3M and JLU) to take the next step.This work was made in the framework of project MINOTOR that has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 730028

"La modernité dure longtemps". Penser la discordance des temps avec C. Charle

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Etude expérimentale des décharges électriques impulsionnelles nanoseconde à pression atmosphérique. Application au traitement des effluents gazeux et à la décontamination de surface

Ce travail porte sur l étude des décharges électriques filamentaires et leurs applications environnementales. La première partie est consacrée à l étude d une décharge couronne alimentée par des impulsions de tensions positives ultra-courtes (générateur de Marx). L analyse des caractéristiques électriques de la décharge a permis d identifier les différentes phases : initiation, propagation et phase résistive. L influence des paramètres de l impulsion (amplitude, front de montée, largeur) sur les caractéristiques énergétiques des streamers a été étudiée. L efficacité de production d espèces actives dans l air est en particulier améliorée en limitant la quantité d énergie dissipée après la jonction à la cathode. L élimination de trois composés organiques volatiles (propane, isopropanol et propène) a mis en évidence la complexité de la cinétique de dégradation et la formation de sous-produits indésirables (ozone, aldéhydes, cétones). Le couplage de la décharge à un catalyseur à base de MnO2 a permis d améliorer les performances du procédé et d éliminer en partie ces composés. La deuxième partie est consacrée au développement d une décharge à barrière diélectrique coplanaire utilisée pour la décontamination chimique et biologique de surface. La dégradation d un simulant de l agent neurotoxique VX a montré que les espèces réactives de l oxygène et le taux de contamination initial influent sur le rendement. Le procédé s est révélé très efficace pour des opérations de stérilisation sur la bactérie Escherichia coli. Les principaux processus d inactivation sont mis en évidence : érosion chimique par les espèces oxydantes, rupture de la membrane sous l effet des espèces chargéesThis work deals with the study of filamentary electrical discharges and their applications for environmental purposes. The first part concerns the study of a corona discharge driven by ultra-short positive high voltage pulses (Marx generator). Electrical signals are analyzed in order to identify the typical steps of the discharge : initiation, propagation and conduction. The influence of pulse parameters (amplitude, width, rise time) on streamers characteristics is studied. The production efficiency of active species in air is especially improved when reducing the amount of energy dissipated after cathode junction. The removal of three volatile organic compounds (propane, isopropyl alcohol and propene) shows that the kinetic mechanism is complex and that several undesirable byproducts can be formed. When coupling the discharge with a MnO2-based catalyst, the process efficiency is improved and the byproducts are partly removed. In a second part, a coplanar dielectric barrier discharge is developed for chemical and biological decontamination of surfaces. The decomposition of a simulant of neurotoxic agent VX shows that reactive oxygen species and initial contamination rate have an effect on the decontamination efficiency. The process is very effective for the sterilization of bacteria Escherichia coli. The main inactivation processes are highlighted : chemical erosion by oxidizing species, membrane rupture due to charged species.ROUEN-BU Sciences (764512102) / SudocROUEN-BU Sciences Madrillet (765752101) / SudocSudocFranceF