Publications

2015

• What is making plasma/catalyst couplingffdifferent from regular catalysis?
  
  • Guaitella Olivier
  , 2015.
• Achievements in Space Science: Capacity building, GIRGEA : 1991-2015
  
  • Amory-Mazaudier Christine
  , 2015. This paper presents the achievements made during the last 2 decades in the framework of scientific international projects IEEY (International Equatorial Electrojet Year), IHY (International heliophysical Year) and ISWI (International Space Weather Initiative). The topics are: - Deployment of tools and capacity building: teams in Côte dIvoire, Burkina Faso, Vietnam, Egypt Algeria, Morocco, RDC, RC etc - Fields of research introduced in Africa : Heliophysics, Space Weather, electrodynamics coupling between high and low latitudes, TIEGCM modeling of equatorial electrojet and disturbance dynamo, etc - Future development in Africa: new tools needed in Africa to improve the research : interferometers incoherent scatter radar, equatorial chain of ionosonde etc
• Ionospheric response to St. Patricks day geomagnetic storm of 2015
  
  • Nava B.
  • Rodríguez-Zuluaga J.
  • Alazo-Cuartas K.
  • Kascheyev Anton
  • Migoya-Orue Yenca
  • Radicella S.
  • Amory-Mazaudier Christine
  • Fleury Rolland
  , 2015. In the present work the effects of the largest geomagnetic storm of the current solar cycle have been studied. The event started on March 17th 2015 with its main phase lasting about 18 hours and the longitudinally symmetric (SYM-H) disturbance index reaching a minimum value of -234 nT. TEC data derived from a set of approximately 200 GNSS receivers distributed worldwide have been analyzed. During the main phase of the storm very large TEC enhancements have been observed in the American sector with the exception of the Northern mid-latitudes where a TEC decrease has been detected. Subsequently, in the recovery phase, a TEC lowering has been identified mainly in the southern part of South America. In the Euro-African sector a general TEC increase has been noticed during the main phase of the storm, followed by a TEC reduction during the day after. Concerning the Asian sector, not remarkable TEC enhancements have been noticed during the day 17th, while a strong negative effect has been identified during the recovery phase on day 18th at mid latitudes in both hemispheres. In order to interpret the TEC enhancements and decreases observed in the different geographic sectors, the relevant ionospheric currents have been analyzed using the data collected by three arrays of magnetometers located in the corresponding geographic sectors. We then characterized the effects of the Prompt Penetration of the magnetospheric Electric Field (PPEF) and the Disturbance Dynamo Electric Field (DDEF) with particular focus on the low-latitude ionospheric regions. To complement the information about the ionosphere behavior during the period considered, ionosonde-derived peak parameter values have also been analyzed for a number of selected stations.
• Climatology of equatorial electron-density perturbations observed by DEMETER satellite (2005-2010) at night-time
  
  • Nguyen Chien-Thang
  • Berthelier Jean-Jacques
  • Amory-Mazaudier Christine
  , 2015. During the six-years of Demeter satellite, electron density perturbations at around 650km observed at the equator during night-time are analyzed. Those perturbations are classified following morphological criteria in 4 classes D1 to D4 [while there is no expected increase of Ne at night-time, D1 : a simple increase of Ne, D2 : 2 increases of Ne, D3: a plateau of electron density and D4 : a plateau with some decreases]. The most common perturbations are the D3 ones. The D3 perturbations occur mainly around 22.30 MLT, at latitudes /- 15° from the geomagnetic equator. The D3 type exhibits maximum at the equinoxes. The vernal maximum is greater than the autumnal one. There are more events ( 18%) during the years of the deep minimum (2006-2009) that during the year 2005 and 2010 . In this paper the authors will present the climatology and interpretation of those D-type perturbations.
• Validation of Inductively Coupled Plasmas Sustained in Halogen Chemistries
  
  • Agarwal Ankur
  • Foucher Mickaël
  • Rauf S.
  • Booth Jean-Paul
  • Chabert Pascal
  • Collins Ken
  , 2015.
• Detection of Biomedically Relevant Reactive Oxygen Species in Atmospheric Pressure Plasmas
  
  • Schröter Sandra
  • Bredin Jérôme
  • Niemi K.
  • Dedrick J.
  • Foucher Mickaël
  • de Oliviera N.
  • Joyeux D.
  • Nahon Laurent
  • Booth Jean-Paul
  • Wagenaars E.
  • Gans T.
  • O'Connell D.
  , 2015.
• A Comprehensive Quantitative Study of Low Pressure Inductively-Coupled Plasmas in Cl<SUB>2</SUB>, O<SUB>2</SUB> and Mixtures
  
  • Booth Jean-Paul
  • Foucher Mickaël
  • Marinov Daniil
  • Chabert Pascal
  • Agarwal Ankur
  • Rauf S.
  , 2015. and O2 are widely used in semi-conductor fabrication for gate etching and photo-resist stripping. Moreover they are an archetype for plasmas in simple electronegative gases with the advantage that techniques exist to measure the densities of nearly all their stable and reactive species. They provide an opportunity to benchmark models such as the Hybrid Plasma Equipment Model. We are then undertaking a comprehensive set of measurements in the pure gases and their mixtures. The plasma is sustained in a cylindrical chamber (55 cm diameter,10 cm height) by a 4-turn planar coil excited at 13.56 MHz above a dielectric window. Pure gases (Cl2 and O2) were studied over a range of pressure [5-80 mTorr] and RF power [50-550 W]. The effect of O2 addition (0-100%) to Cl2 plasmas was studied at 10 mTorr 500W. The electron density was determined by hairpin resonator probe. The Cl and O atom absolute densities and surface reaction coefficients were obtained by Two-Photon Absorption Laser- Induced Fluorescence. A novel ultra-broadband high sensitivity absorption bench was used to measure ground state and vibrationally excited Cl2 and vibrationally excited O2, as well as OCl, OClO and Cl- ions. In all gas mixtures, the electron density was observed to increase initially with gas pressure, pass through a maximum and then decrease at higher pressure. In O2 a broad maximum is observed around 40 mTorr, whereas for Cl2 the electron density peaks at 10 mTorr before dropping sharply. This difference can be attributed to rapid dissociative attachment of electrons in the case of Cl2. In all cases the electron density increases with RF power. In O2, highly vibrationally excited molecules O2(v) were observed ( with v up to 18), and analysis of the rotational structure of the O2 Schumann-Runge bands showed rotational temperatures (=translational temperatures) ranging from 400 K (10mTorr 100W) to 900 K (80 mTorr 500W). The non-equilibrium vibrational distribution may be attributed to electron impact excitation combined with low rates of V-T energy transfer processes in O2. In contrast, 51 Monday Afternoon, October 19, 2015 in pure Cl2 the vibrational temperature is equal to the gas translational temperature, (~1000K) due to efficient V-T transfers between Cl2 and Cl atoms. In Cl2/O2 mixtures the densities of electrons and Cl and O atoms all decreased when O2 or Cl2 is added to the pure gas (Cl2 or O2). This coincides with the formation of ClO and OClO, which consumes the atoms which are easier to ionize than molecules. We are currently working on modeling of these results to obtain a deeper understanding of the kinetics of Cl2/O2 plasmas.
• Harmonic signatures of NTC waves observed by WHISPER instruments on board the Cluster mission: interpretations and questions
  
  • Décréau Pierrette
  • Rauch Jean-Louis
  • Vallières Xavier
  • Galkina I.
  • El-Lemdani Mazouz F.
  • Canu Patrick
  • Darrouzet F.
  • Rochel Grimald S.
  , 2015.
• A study of equatorial noise gyroharmonics frequency values with Cluster wave data
  
  • Cornilleau-Wehrlin Nicole
  • Sochorova Z.
  • Santolík O.
  • Pickett J. S.
  • Canu Patrick
  • Grison B.
  , 2015.
• Fourier spectra: slopes and breaks
  
  • Belmont Gérard
  • Rezeau Laurence
  • Dorville Nicolas
  , 2015. When aiming at comparing the data of fluctuations with turbulence theories, it is necessary to determine reliable spectra, from which slopes (spectral indexes) can be deduced when they exist, as well as the positions of the breaks between different slopes. Unfortunately, when using FFT on data in a finite interval, a large uncertainty exists in those results, due to the global trend in the interval and to the effects of the limiting window. One of the most striking effects of these phenomena is the presence of large amplitude "hairs" affecting the spectrum when it is not smoothed or averaged on successive intervals. Using different windows can slightly alleviate the problem but not really solve it. In these conditions, beyond the questions of accuracy, the very existence of slopes and breaks can be questioned and authors can even be suspected to be fooled by their frenzy to detect straight lines inside the hairy spectra. We present here a new method to suppress the artificial hairs of the spectra in an objective way. We also present results obtained by the method, for turbulence spectra and also for spectrograms and polarization studies.
• Experimental and numerical study on the dynamics of a us helium plasma gun discharge with various amounts of N<SUB>2</SUB> admixture
  
  • Bourdon Anne
  • Darny T.
  • Robert E.
  • Pechereau F.
  • Viegas Pedro
  • Pouvesle Jm
  , 2015.
• Modelling the influence of neutral gas heating mechanisms on particle densities in inductively coupled chlorine discharges
  
  • Gibson Andrew
  • Gans T.
  • Foucher Mickaël
  • Marinov Daniil
  • Chabert Pascal
  • Kushner M.J.
  • Booth Jean-Paul
  , 2015.
• Experimental and numerical study of the dynamics of a μs helium plasma gun discharge with various amounts of N2 admixture
  
  • Bourdon Anne
  • Viegas Pedro
  • Darny Thibault
  • Robert Eric
  • Pouvesle Jean-Michel
  • Pechereau François
  , 2015, 60 (9), pp.http://meetings.aps.org/link/BAPS.2015.GEC.NR1.3. These last years, atmospheric pressure plasma jets formed by pulsed helium discharges ignited in thin dielectric tubes have been extensively studied due to their potential for biomedical applications. So far, most experiments have been dedicated to the study of the plasma plume. For endoscopic treatments, it is also important to better understand and optimize the propagation of discharges in long dielectric tubes as catheters. First we present an experimental and numerical study on the dynamics of a s helium plasma discharge with N2 admixture in a long dielectric tube. We compare the velocity of the discharge front for various amounts of N2 and dierent applied voltages and show a good agreement between experiments and simulations. Second, we compare time-resolved measurements and simulations of longitudinal and radial electric elds associated with plasma propagation in the dielectric tube and in the plasma plume. It is interesting to note that measurements obtained with a probe located outside the dielectric tube are in excellent agreement with simulations. This allows to infer from simulations the time evolution of the electric eld on the discharge axis which is a key parameter for applications. Acknowledgment: The authors acknowledge the computational resources of the Mesocentre of Ecole Centrale Paris.
• Vibrational kinetics in Cl<SUB>2</SUB> and O<SUB>2</SUB> low-pressure inductively-coupled plasmas
  
  • Booth Jean-Paul
  • Foucher Mickaël
  • Marinov Daniil
  • Chabert Pascal
  • Annusova Adriana
  • Guerra V.
  • Agarwal Ankur
  • Rauf S.
  , 2015.
• Reactive species generated in atmospheric-pressure plasmas with water admixtures for biomedical applications: Absolute measurements and numerical simulations
  
  • Schröter Sandra
  • Bredin Jérôme
  • West A.
  • Niemi K.
  • Dedrick J.
  • de Oliviera N.
  • Joyeux D.
  • Nahon L.
  • Foucher Mickaël
  • Booth Jean-Paul
  • Wagenaars E.
  • Gans T.
  • O'Connell D.
  , 2015.
• A new statistical study of the magnetopause features seen by Cluster
  
  • Rezeau Laurence
  • Belmont Gérard
  • Dorville Nicolas
  • Molinier C.
  , 2015. The BV method is based on both magnetic field and velocity measurements to determine the magnetopause normal with an improved accuracy from data of one spacecraft. It makes possible a reliable determination of the normal magnetic field and therefore to disentangle a tangential magnetopause from a reconnected one. We will show statistics on the determination of the normal component of the magnetic field and on other properties such as the magnetic shear angle of the tangential component. One of the byproducts of the method is the thickness of the boundary. We will discuss the similarities and differences with the statistics obtained by multi-spacecraft methods when both methods are reliable. The role in particular of a flow going through the magnetopause will be evidenced.
• Alteration of the magnetic structure of magnetic clouds inside the magnetosheath: a statistical approach
  
  • Turc Lucile
  • Fontaine Dominique
  • Kilpua E. K. J.
  • Escoubet P.
  , 2015.
• Impact of the bow shock and the magnetosheath on the magnetic clouds geoeffectivity : observations and hybrid simulations
  
  • Fontaine Dominique
  • Turc Lucile
  • Savoini Philippe
  • Modolo Ronan
  , 2015.
• Energy dissipation rate of compressible solar wind turbulence
  
  • Sahraoui Fouad
  , 2015.
• On the origin of ULF broadband electromagnetic fluctuations in the polar cusps
  
  • Grison B.
  • Cornilleau-Wehrlin Nicole
  , 2015.
• 2D PIC Simulations of the terrestrial ion Quasi-perpendicular Foreshock: origin of back streaming ions
  
  • Savoini Philippe
  • Lembège Bertrand
  , 2015.
• Whistler-mode waves and electromagnetic ion cyclotron waves in plasmaspheric plumes
  
  • Santolík O.
  • Kolmasova Ivana
  • Usanova M.
  • Darrouzet F.
  • Cornilleau-Wehrlin Nicole
  , 2015.
• 2D fluid simulations of discharges at atmospheric pressure in reactive gas mixtures
  
  • Bourdon Anne
  , 2015.
• TC-1 observations on nonlinear ULF waves and cold ion energization in the dayside magnetosphere
  
  • Cai C.I.
  • Rème H.
  • Cao J.B.
  • Dandouras I.
  • Parks G. K.
  • Fontaine Dominique
  , 2015.
• Spontaneous Growth of Nonlinear Structures Upstream of Earth's Bow Shock
  
  • Parks G. K.
  • Lee E.S.
  • Canu Patrick
  • Lin N.
  • Hong J.
  • Yang Z. W.
  • Liu Y.
  • Fu S. Y.
  • Dandouras I.
  • Rème H.
  • Goldstein M. L.
  , 2015.