Publications

2010

• Plasma propulsion with electronegative gases
  
  • Popelier Lara
  • Aanesland Ane
  • Chabert Pascal
  , 2010.
• Fast ionization wave experiments on fast gas heating
  
  • Mintoussov E.I.
  • Lacoste D.A.
  • Pendleton S.J.
  • Popov N.A.
  • Stancu G.D.
  • Laux C.O.
  • Starikovskaia Svetlana
  , 2010.
• Time-resolved electric field measurements in nanosecond surface dielectric barrier discharge
  
  • Sagulenko P.N.
  • Mintoussov E.I.
  • Starikovskaia Svetlana
  , 2010.
• Les plasma ion-ion appliqués à la propulsion spatiale
  
  • Aanesland Ane
  , 2010.
• Etude théorique d'une micro décharge à cathode creuse dargo
  
  • Lazzaroni Claudia
  • Chabert Pascal
  • Rousseau Antoine
  • Sadeghi N.
  , 2010.
• Plasma inductif en Cl<SUB>2</SUB>/Ar : comparaison entre simulations hybrides et expériences
  
  • Sarot Rodolphe
  • Despiau-Pujo Emilie
  • Chabert Pascal
  • Booth Jean-Paul
  • Gatilova L.
  • Bouchoule S.
  , 2010.
• Time-resolved nanosecond imaging of the propagation of a corona-like plasma discharge in water at positive applied voltage polarity
  
  • Ceccato P H
  • Guaitella Olivier
  • Rabec Le Gloahec M
  • Rousseau Antoine
  Journal of Physics D: Applied Physics, IOP Publishing, 2010, 43 (17), pp.175202. The present paper is an experimental study of a pulsed filamentary plasma discharge inside liquid water in pin to plane electrode configuration. Time resolved electrical and imaging diagnostics have been performed. The initiation and the propagation of the discharge have been studied for several experimental parameters. The propagation is continuous and is followed by reilluminations at low water conductivity. The measured propagation velocity of the plasma discharge is 30km/s for the secondary positive mode. This velocity was found to be surprisingly constant whatever the experimental parameters and especially as a function of the water conductivity. (10.1088/0022-3727/43/17/175202)
  DOI : 10.1088/0022-3727/43/17/175202
• Alfvén wave driven giant polar plumes
  
  • Pinto Rui
  • Grappin Roland
  • Léorat Jacques
  , 2010, 12, pp.14362. We present the first results of simulations of giant polar plumes generated by Alfvénic motions of their magnetic footpoints. We use a 2.5D axisymmetric MHD numerical model of an isothermal corona and slow solar wind with transparent boundary conditions. Alfvén waves are continuously injected from the coronal base and a dense jet (plume) forms just above a small magnetic bipole embedded in an unipolar flux region. The jet presents a series of blobs which propagate outwards along its axis as slow mode wavefronts.
• 2D PIC simulations of a curved supercritical shock: dynamics of the whistler precursor
  
  • Stienlet J.
  • Savoini Philippe
  • Lembège Bertrand
  , 2010, 12, pp.11159. The whistler precursor emitted from the curved terrestrial shock front plays an important role in pre-decelerating and heating the incoming solar wind. Most previous works have mainly analyzed the features of the whistler precursor emission for a 1D planar shock where it is forced to propagate along the shock normal (Liewer and al, 1991) or to propagate obliquely with respect to a fixed shock normal direction in 2D planar shock simulation (Krauss-Varban et al., 1995). In the present case, the dynamics of the precursor is analyzed with the help of a 2D full particle simulation for a continuously curved shock within the angular range 90o >= ?Bn >= 45o where ?Bn is the angle between the shock normal and the upstream magnetostatic field. Both electrons and ions dynamics are described by a self consistent approach. Our results show that (i) the whistler precursor extends far from the shock front mainly along the magnetostatic field (projected on the simulation plane) and not along the shock normal; (ii) the width of these curved wave fronts (precursor) strongly decreases when moving far from the shock front; (iii) at the shock front, the precursor is emitted within an angular range much larger than that predicted by linear theory; (iv) the damping rate of the whistler precursor is analyzed for different directions of the shock normal. Wave particle energy transfer is analysed, and these results will be discussed and compared with previous 1D and 2D simulations of planar shocks; (v) the whistler precursor is not monochromatic, and interferences between modes are evidenced by beats and wave-packets in front of the shock. The impact of this effect on damping rate measurements will be discussed.
• Search for a self-consistent solar wind model
  
  • Grappin Roland
  • Léorat Jacques
  • Leygnac Sebastien
  • Pinto Rui
  , 2010, 12, pp.7040. We describe a solar wind 1-fluid 1D model which is (1) time-dependent (2) includes transition region down to solar surface (3) uses a moderate number of grid points to enable further generalization to 2D/3D. The present model enables to study the response of the transition region and corona to photospheric pressure perturbations, including the solar wind up to several tens of solar radii. A simple chromosphere model with uniform temperature is used, in two different forms, either taking into account partial ionization or not. We study in particular viscous heating and stability of the transition region oscillations when varying the parameters of the model.
• Anisotropic developed MHD turbulence
  
  • Grappin Roland
  • Müller Wolf-Christian
  , 2010, 12, pp.6787. MHD turbulence with a mean field is of importance to understand the non-adiabatic cooling of the expanding solar wind plasma with heliocentric distance. The first theory was proposed by Iroshnikov and Kraichnan who proposed that the cascade towards small scales would be slowed down by the decorrelation of oppositely propagating Alfvén wavepackets. This theory did not put much accent on the anisotropy of the phase velocity of the waves, depending on the angle of the wavevector with mean field. A completely different picture has been since proposed which on the contrary insisted that a 1D-like fast (Kolmogorov-like) cascade should occur along the direction perpendicular to the mean field, with a very reduced spectral width in the parallel direction, this width being given by the balance between the perpendicular non-linear time and the linear parallel propagation time. The anisotropy predicted by this theory is in a sense maximal. We give here a different picture, resulting from large Reynolds simulations, in which the anisotropy is more moderate than that predicted by the critical balance theory. In this new picture, the spectral scaling is the same in all directions, only the dissipation wavenumber depends on the angle between the wave vector and the mean field. The resulting anisotropy has a simple dependance on the mean field.
• Coupling Photosphere and Corona: Linear and Turbulent Regimes
  
  • Verdini Andrea
  • Grappin Roland
  • Velli Marco
  , 2010, 12, pp.14380. In a recent work Grappin et al. [1] have shown that low- frequency movements can be transmitted from one footpoint to the other along a magnetic loop, thus mimicking a friction effect of the corona on the photosphere, and invalidating the line-tying approximation. We consider here successively the effect of high frequencies and turbulent damping on the process. We use a very simple atmospheric model which allows to study analytically the laminar case, and to study the turbulent case both using simple phenomenological arguments and a more sophisticated turbulence model [2]. We find that, except when turbulent damping is such that all turbulence is damped during loop traversal, coupling still occurs between distant footpoints, and moreover the coronal field induced by photospheric movements saturates at finite values.
• Europlanet-RI IDIS - A Data Network in Support of Planetary Research
  
  • Schmidt Walter
  • Capria Maria Teresa
  • Chanteur Gérard
  , 2010, 12, pp.4760. The "Europlanet Research Infrastructure - Europlanet RI", supported by the European Commission's Framework Program 7, aims at integrating major parts of the distributed European Planetary Research infrastructure with as diverse components as space exploration, ground-based observations, laboratory experiments and numerical modeling teams. A central part of Europlanet RI is the "Integrated and Distributed Information Service" (IDIS), a network of data and information access facilities in Europe via which information relevant for planetary research can be easily found and retrieved. This covers the wide range from contact addresses of possible research partners, laboratories and test facilities to the access of data collected with space missions or during laboratory or simulation tests and to model software useful for their interpretation. During the following three years the capabilities of the network will be extended to allow the combination of many different data sources for comperative studies including the results of modeling calculations and simulations of instrument observations. Together with the access to complex databases for spectra of atmospheric molecules and planetary surface material IDIS will offer a versatile working environment for making the scientific exploitation of the resources put into planetary research in the past and future more effective. Many of the mentioned capabilities are already available now. List of contact web-sites: Technical node for support and management aspects: http://www.idis.europlanet-ri.eu/ Planetary Surfaces and Interiors node: http://www.idis-interiors.europlanet-ri.eu/ Planetary Plasma node: http://www.idis-plasma.europlanet-ri.eu/ Planetary Atmospheres node: http://www.idis-atmos.europlanet-ri.eu/ Small Bodies and Dust node: http://www.idis-sbdn.europlanet-ri.eu/ Planetary Dynamics and Extraterrestrial Matter node: http://www.idis-dyn.europlanet-ri.eu
• Remote sensing of plasma density fluctuations and wave source characteristics by means of chorus waves multi point phase correlation analysis: Cluster and THEMIS measurements
  
  • Agapitov Oleksiy
  • Krasnoselskikh Vladimir
  • Dudok de Wit Thierry
  • Rolland Guy
  • Santolik Ondrej
  • Angelopoulos Vassilis
  • Le Contel Olivier
  , 2010, pp.13307. We present the case study of multi spacecraft observations of the whistler wave emissions in the outer Earth magnetosphere near the geomagnetic equator. The Cluster project WBD data and THEMIS project Electric Field Instrument (EFI) and Search Coil Magnetometer (SCM) measurements were used to determine the spatial correlation scale of the chorus source region. We analyze simultaneous observations of the same chorus elements registered onboard four THEMIS spacecraft in 2007 when all the spacecraft were on the same orbit and onboard four Cluster spacecraft during 2001-2002. The transverse to the background magnetic field cross spacecraft distances were from 200 to 6000 km. The events chosen for analysis satisfy the conditions allowing the estimation of the chorus generation region spatial scale. The electron density fluctuations correlation scale is found to be much smaller then the chorus source region scale. The quasi-longitudinal to magnetic filed propagation gives rise to an opportunity for distinguishing the parallel and transverse perturbation scales and estimating the distance to the source along the magnetic field. The discrete chorus elements were observed in the frequency range 0.15—0.25 of the local electron gyrofrequency that is typical for the outer magnetosphere. The field-aligned Poynting flux of whistler emissions shows that they propagate along the magnetic field lines in the direction away from the magnetic field minimum that is consistent with the waves being generated there. The averaged amplitude correlation analysis allows to estimate the characteristic spatial half-width of the source region transverse to the local magnetic field to be about 2800—3200 km. The correlation scale of electromagnetic permeability and corresponding electron density fluctuations are estimated in the frame of geometrical optics approximation. The phase cross correlation time dependence gives correlation scale from 250 to 500 km transverse to the local magnetic field. The increasing of the fluctuation correlation scale with the geocentric distance is found. The distance to the source region is found to vary from 400 to 2000 km. From this one can suggest that the source can move with the characteristic velocity about 1—2 thousands km/sec along the magnetic field line.
• The heat engine analogy in understanding of toroidal rotation: thermodynamics of L-H spin-up
  
  • Gürcan Özgür D.
  • Diamond P.H.
  • Mcdevitt C.J.
  • Kosuga Y.
  , 2010 (oral).
• Fluctuations measurements from Doppler Reflectometry On Tore Supra
  
  • Hennequin Pascale
  , 2010.
• Collective light scattering for the study of transport and fluctuations in magnetized plasmas : the Hall thruster case study
  
  • Tsikata Sedina
  • Honoré Cyrille
  • Grésillon D.
  • Lemoine N.
  , 2010.
• Limitations of multispacecraft data techniques in measuring wave number spectra of space plasma turbulence
  
  • Sahraoui Fouad
  • Belmont Gérard
  • Goldstein M.L.
  • Rezeau Laurence
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2010, 115 (A04206), pp.10. Unambiguous determination of spatial properties of space plasma turbulence from temporal measurements has been one of the major goals of the Cluster mission. For that purpose, techniques, such as the k filtering, have been developed. Such multipoint measurement techniques combine several time series recorded simultaneously at different points in space to estimate the corresponding energy density in wave number space. Here we present results of such an analysis, including a detailed discussion of the errors and limitations that arise due to the separation of the spacecraft and the quality of the tetrahedral configuration. Specifically, we answer the following questions: (1) What are the minimum and maximum scales that can be accurately measured given a specific distance between the satellites? (2) How important is the geometry of the tetrahedron, and what is the relationship of that geometry to spatial aliasing? (3) How should one perform a proper integration of the angular frequencies to infer wave number spectra, and what role does the Doppler shift play when the magnetofluid is rapidly convecting past the spacecraft? We illustrate the results with analyses with both simulated and Cluster magnetometer data recorded in the solar wind. We also discuss the potential impact on future multispacecraft missions, such as Magnetospheric MultiScale and Cross-Scale. (10.1029/2009JA014724)
  DOI : 10.1029/2009JA014724
• The excitation structure in a micro-hollow cathode discharge in the normal regime at medium argon pressure
  
  • Lazzaroni Claudia
  • Chabert Pascal
  • Rousseau A.
  • Sadeghi N
  Journal of Physics D: Applied Physics, IOP Publishing, 2010, 43 (12), pp.124008. A microplasma is generated in the microhole (400 µm diameter) of a molybdenum-aluminamolybdenum sandwich (MHCD type) at medium pressure (30-200 Torr) in pure argon. Imaging and emission spectroscopy have been used to study the light emission mechanisms in the microdischarge. We find that emission intensities of both argon atom and argon ion lines present sharp peaks located near the cathode, and that the position of these peaks moves toward the cathode with increasing gas pressure. An ionizing-sheath model has been developed to calculate the evolution of the sheath thickness as a function of the gas pressure. This model includes the ratio between the ion flux coming from the bulk of the plasma and the ion flux created in the sheath and also accounts for the gas heating in the microhole. The variation of the calculated ionizing sheath thickness as a function of pressure agrees well with the variation of the measured peak positions. The case of a sheath free of ionization has also been considered. However, the comparison between experiments and the various theories shows that a significant fraction of the ionization occurs in the sheath. (10.1088/0022-3727/43/12/124008)
  DOI : 10.1088/0022-3727/43/12/124008
• On electric field measurements in surface dielectric barrier discharge
  
  • Starikovskaia S M
  • Allegraud Katia
  • Guaitella Olivier
  • Rousseau A
  Journal of Physics D: Applied Physics, IOP Publishing, 2010, 43 (12), pp.124007. Analysis of available data on electric field measurements in surface dielectric barrier discharges (DBDs) was carried out. Experimental measurements of emission spectra in triggered and non–triggered sinusoidal surface DBD were performed. The obtained results were used for the calculation of electric field value. The comparison of data obtained and the results published by other authors is presented. (10.1088/0022-3727/43/12/124007)
  DOI : 10.1088/0022-3727/43/12/124007
• Production of molecules on a surface under plasma exposure: example of NO on pyrex
  
  • Marinov D
  • Guaitella O
  • Rousseau A
  • Ionikh Y
  Journal of Physics D: Applied Physics, IOP Publishing, 2010, 43 (11), pp.115203. We propose a new experimental approach to the study of surface-catalyzed nitric oxide production under plasma exposure. Stable nitrogen species are grafted to the surface of pyrex discharge tube during N 2 plasma pretreatment. These species are trapped by surface active sites and being exposed to O 2 plasma, they initiate production of NO molecules, which are detected using tunable diode laser absorption spectroscopy. Supposing that nitrogen species are adsorbed N atoms, we estimate the initial surface coverage [ N ads ]=3·10 13 cm -2. That gives an assessment of the lower boundary of the surface active sites density. (10.1088/0022-3727/43/11/115203)
  DOI : 10.1088/0022-3727/43/11/115203
• Turbulence measurements during dimensionless parameters scans on Tore Supra using Doppler reflectometry
  
  • Vermare Laure
  • Hennequin Pascale
  • Gürcan Özgür D.
  • Honoré Cyrille
  • Bourdelle C.
  • Aniel T.
  • Clairet F.
  • Dumont R.
  • Fenzi C.
  • Sabot R.
  • Tore Supra Team
  , 2010 (oral).
• Turbulence et dissipation à petite échelle dans le vent solaire
  
  • Sahraoui Fouad
  • Goldstein M.L.
  • Abdul-Kader Khaldoun
  • Belmont Gérard
  • Rezeau Laurence
  • Robert Patrick
  • Canu Patrick
  , 2010. Turbulence at MagnetoHydroDynamics (MHD) scales of the solar wind has been studied for more than three decades, using data analyzes, theoretical and numerical modeling. However smaller scales have not been explored until very recently. Here, we review recent results on the first observation of cascade and dissipation of the solar wind turbulence at the electron scales. Thanks to the high resolution magnetic and electric field data of the Cluster spacecraft, we computed the spectra of turbulence up to 100 Hz (in the spaceraft reference frame) and found evidence of energy dissipation around the Doppler-shifted electron gyroscale fe . Before its dissipation, the energy is shown to undergo two cascades: a Kolmogorov-like cascade with a scaling f−1.6 above the proton gyroscale, and a new f−2.3 cascade at the sub-proton and electron gyroscales. Above fe the spectrum has a steeper power law f−4.1 down to the noise level of the instrument. Solving numerically the linear Maxwell-Vlasov equations combined with recent theoretical predictions of the Gyro-Kinetic theory, we show that the present results are consistent with a scenario of a quasi-two-dimensional cascade into Kinetic Alfv´en modes (KAW). New analyses of other data sets, where the Cluster separation ( 100 km) allowed us to explore the sub-proton scales using the k-filtering technique, and to confirm the 2-D nature of the turbulence at those scales.
• Shell Models and the possibility of application to fusion plasmas
  
  • Gürcan Özgür D.
  • Hennequin Pascale
  • Garbet X.
  • Diamond P.H.
  • Vermare Laure
  • Casati A.
  • Falchetto G.
  , 2010 (oral).
• Météorologie de l'Espace en Afrique (II) le programme ISWI - International Space Weather Initiative
  
  • Amory-Mazaudier Christine
  • Kobea A.
  • Ouattara F.
  • Dinga B.
  • Doumbia V.
  • Hady A.
  • Hounginou E.
  • Kahindo B.
  • Madougou S.
  • Mahrous A.
  • Ndekatou T.
  • Uwamahoro J.
  • Zaourar N.
  • Bock Olivier
  • Cohen Y.
  • Damé Luc
  • Fleury Rolland
  • Lassudrie-Duchesne Patrick
  • Petitdidier Monique
  , 2010, pp.12 p..