Publications

2009

• Heat and Particle Transport Experiments in Tore Supra and HL-2A with ECRH and SMBI
  
  • Zou X. L.
  • Song S.
  • Giruzzi G.
  • Garbet X.
  • Honoré Cyrille
  • Ségui J.-L.
  • Elbeze D.
  • Clairet F.
  • Sabot R.
  • Bucalossi J.
  • Hennequin Pascale
  • Lenholm M.
  • Magne R.
  • Tore Supra Team
  , 2009, ECA Vol. 33E (P-4.210).
• LONGITUDINAL AND TRANSVERSE COILED GIANT MAGNETOIMPEDANCE TRANSDUCERS PRINCIPLE, MODELING AND PERFORMANCES
  
  • Moutoussamy Joël
  • Coillot Christophe
  • Chanteur Gérard
  • Alves Francisco
  , 2009, pp.M3P.076. New Giant Magneto-Impedance structures are studied both experimentally and theoretically. These transducers are made with one or two anisotropic nanocrystalline ribbons and the magnetic excitation is provided by coils mounted either in transverse or longitudinal direction. Very high sensitivities up to 1000V/T have been achieved even at low excitation frequencies from 5kHz to 500kHz and low consumption driving current (5-10mA). The Eddy current phenomenon and magnetic domain considerations are used to determine a semi-theoretical model of impedance. Intrinsic sensitivity computation approach emphasizes on the role of the differential magnetic permeability in coiled GMI detection performances.
• Analysis of energetic efficiency and kinetics of intermediates in the problem of plasma assisted ignition
  
  • Starikovskaia Svetlana
  • Kosarev I.N.
  • Popov N.A.
  • Starikovskii A.Yu.
  , 2009.
• Search for a self-consistent solar wind model
  
  • Grappin Roland
  • Léorat Jacques
  • Leygnac Sebastien
  • Pinto Rui
  , 2010, 1216, pp.24-27. We describe here 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 ten solar radii. A simple chromosphere model with uniform temperature is used, in two different forms, either taking into account partial ionization or not. We show here how the amplitude of the response and associated viscous heating vary when attempting to decreasing the dynamical viscosity to approach realistic values. (10.1063/1.3395848)
  DOI : 10.1063/1.3395848
• Coronal Inflows and Giant Polar Plumes
  
  • Pinto Rui
  • Grappin Roland
  • Léorat Jacques
  , 2010, 1216, pp.80-83. We present the first results of simulations of giant polar plumes and coronal flows. We use a 2.5D axisymmetric MHD numerical model of an isothermal corona and slow solar wind. A plume is generated just above a small magnetic bipole embedded in an unipolar flux region which is perturbed by Alfvén waves injected from the coronal base. The boundary conditions are transparent. The results are compared to those obtained previously with a 1D wind model in which plumes are generated as a consequence of variations of the heating and flux-tube expansion parameters. (10.1063/1.3395968)
  DOI : 10.1063/1.3395968
• Coupling Photosphere and Corona: Linear and Turbulent Regimes
  
  • Verdini Andrea
  • Grappin Roland
  • Velli Marco
  , 2010, 1216, pp.28-31. 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. (10.1063/1.3395858)
  DOI : 10.1063/1.3395858
• Structures and Intermittency in Small Scales Solar Wind Turbulence
  
  • Sahraoui Fouad
  • Goldstein M. L.
  , 2010, 1216, pp.140-143. (10.1063/1.3395820)
  DOI : 10.1063/1.3395820
• Cascade and dissipation of solar wind turbulence at electron scales
  
  • Sahraoui Fouad
  • Goldstein M. L.
  • Khotyaintsev Y. V.
  • Robert Patrick
  , 2009.
• Studies of new closed and open configurations of multi-planar wire arrays with straight and skewed wires and opacity effects observations at unr 1.4 MA zebra generator
  
  • Kantsyrev Viktor L.
  • Safronova Alla S.
  • Esaulov A. A.
  • Williamson Kenneth M.
  • Shrestha Ishor
  • Weller Michael E.
  • Osborne Glenn C.
  • Yilmaz M. F.
  • Ouart N. D.
  • Shlyaptseva V. V.
  • Rudakov Leonid I.
  • Chuvatin Alexandre S.
  , 2009, pp.1. Summary form only given. Experiments with different Z-pinch loads were performed on 1.4 MA, 100 ns Zebra generator at UNR. The program emphasized investigation of plasma formation, implosion and radiation features as a function of the load configuration: compact multi-planar and cylindrical wire arrays. The multi-planar wire arrays (PWA) were studied in open and closed configuration with Al, stainless steel, Cu, brass, Mo and W wires. In open configurations, for single, double, and triple PWAs, wire rows are parallel to each other and there is magnetic field inside the array from the beginning of the discharge. A new closed configuration, Prism-like triangle PWA, eliminates the global magnetic field inside (as cylindrical arrays) ahead of the plasma flow. Prism-like PWAs (that are not equal to compact cylindrical array) show high flexibility in control of implosion dynamics and precursor formation by switching of wire materials and changing mass ablation rates in prism rows and corners. The spectra modeling, MHD and WADM codes have been used for implosion and stagnation parameters simulation. Electron temperature and density in multiple bright spots reached ~1.4 keV and ~5x1021 cm-3, respectively. With current rise from 0.8 up to 1.3 MA, opacity effects became more pronounced, which may limit X-ray yields from PWA and especially from CCWA loads: much lower peak current yields scaling for CCWAs compared with PWAs; appearance of absorption lines in X-ray spectra, and anisotropy of sub-keV emission from SPWAs. The DPWA was found to be the best X-ray radiator at 1 MA tested at Zebra: it is characterized by combination of larger resistive energy and power gain (25 kJ and 1 TW), small mm-scale size, the possibility of radiation pulse shaping, and easy diagnostics access to plasmas. These characteristics may even be improved by application of a new tested load: DPWA with skewed wires. In this load, an initial axial magnetic filed is created that migh- mitigate the magneto-RT instabilities and provide more effective X-ray generation. The experimental results are summarized and discussed. (10.1109/PLASMA.2009.5227698)
  DOI : 10.1109/PLASMA.2009.5227698
• Etch process control with a deposition-tolerant planar electrostatic probe
  
  • Booth Jean-Paul
  • Keil D.
  • Thorgrimsson C.
  • Nagai M.
  • Albarede L.
  , 2009.
• Broadband absorption with UV Light-Emitting Diodes in a dual-frequency capacitively coupled reactor
  
  • Bredin Jérôme
  • Booth Jean-Paul
  , 2009.
• Etch process control with a deposition-tolerant planar electrostatic probe
  
  • Booth Jean-Paul
  • Keil D.
  • Thorgrimsson C.
  • Nagai M.
  • Albarede L.
  , 2009.
• High-altitude CLUSTER observations related to polar cap arcs
  
  • Fontaine Dominique
  • Teste A.
  , 2009. During quiet periods of Northward IMF, Cluster observed electron acceleration structures at high altitudes along magnetic field lines connected to the polar cap. The electrons are observed to be successively earthward and outward accelerated along orbits crossing polar magnetic field lines at about 10 Earthradii. They form sheets of opposite polarities carrying currents of comparable intensities. The precipitating electrons are accelerated to keV-energies and are accompanied by accelerated ions escaping from the polar ionosphere, which indicates the presence of field-aligned potential drops along magnetic field lines. Both precipitating electrons and outflowing ions form relatively stable and broad structures. The four spacecraft analysis indicates that their orientation is roughly sun-aligned. These characteristics suggest that they represent the high altitude signature of polar cap arcs. Cluster observations associated with a model of transport along magnetic field lines leads to point out the high latitude mantle close to the magnetopause as their possible source region. Finally, we discuss the possible acceleration processes.
• 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
  , 2009 (oral).
• Non stationarity of perpendicular shocks
  
  • Travnicek P.
  • Hellinger P.
  • Lembège Bertrand
  • Savoini Philippe
  , 2009.
• High k spectra in Tore Supra : experiment, theory and modelling
  
  • Hennequin Pascale
  • Vermare Laure
  • Gürcan Özgür D.
  • Trier Elisée
  • Honoré Cyrille
  • Bourdelle C.
  • Casati A.
  • Dumont G.
  • Falchetto G.
  • Garbet X.
  • Sabot R.
  • Clairet F.
  • Tore Supra Team
  , 2009 (oral). http://ttf2009.ucsd.edu/working/abₛtorage/afterₚresentation/HennequinTTF09.pdf
• On plasma rotation in tokamak with magnetic field ripple and no external momentum input
  
  • Fenzi C.
  • Trier Elisée
  • Aniel T.
  • Bourdelle C.
  • Clairet F.
  • Falchetto G.
  • Garbet X.
  • Gil C.
  • Gürcan Özgür D.
  • Hennequin Pascale
  • Lasalle J.
  • Sabot R.
  • Ségui J.-L.
  • Vermare Laure
  • Tore Supra Team
  , 2009.
• Observation of a localized radial electric field inversion in Tore Supra plasmas.
  
  • Trier Elisée
  • Hennequin Pascale
  • Fenzi C.
  • Gürcan Özgür D.
  • Sabot R.
  • Maget P.
  • Bucalossi J.
  • Garbet X.
  • Clairet F.
  • Vermare Laure
  • Bourdelle C.
  • Guimaraes-Filho Z.
  • Falchetto G.
  • Huysmans G.
  , 2009 (oral). http://ttf2009.ucsd.edu/working/abₛtorage/afterₚresentation/trier_TTF09.pdf
• Influence of surface charges on the structure of a dielectric barrier discharge in air at atmospheric pressure: experiment and modeling
  
  • Célestin Sébastien
  • Bonaventura Zdenek
  • Guaitella Olivier
  • Rousseau Antoine
  • Bourdon Anne
  European Physical Journal: Applied Physics, EDP Sciences, 2009, 47, pp.22810. Dielectric barrier discharges (DBD) in air at atmospheric pressure and at low frequency are mainly constituted of thin transient plasma filaments (or microdischarges) with radii of a few hundreds of micrometers. In this work, we consider a point-to-plane geometry with the dielectric covering the plane electrode. Plasma filaments are initiated by streamers, starting from the high-field region close to the point electrode. The plasma filaments deposit charges on the dielectric plate which screen the electric field and lead to an extinction of the discharge filaments. In this work we experimentally demonstrate the synchronous start of several filaments in a time range of less than a few tens of nanoseconds and we show that the charges deposited on the dielectric have a strong impact on the discharge structure. This is validated using a simple electrostatic model. Then, the dynamics of the 2D streamer propagation in the gas gap and its interaction with the dielectric plane is calculated. The influence of space charges and surface charges on the discharge structure are discussed and compared with the experiment. (10.1051/epjap/2009078)
  DOI : 10.1051/epjap/2009078
• Turbulence in the TORE SUPRA Tokamak: Measurements and Validation of Nonlinear Simulations
  
  • Casati A.
  • Gerbaud T.
  • Hennequin P.
  • Bourdelle C.
  • Candy J.
  • Clairet F.
  • Garbet X.
  • Grandgirard V.
  • Gürcan Ö.
  • Heuraux S.
  • Hoang G.
  • Honoré C.
  • Imbeaux F.
  • Sabot R.
  • Sarazin Y.
  • Vermare L.
  • Waltz R.
  Physical Review Letters, American Physical Society, 2009, 102 (16), pp.165005. (10.1103/PhysRevLett.102.165005)
  DOI : 10.1103/PhysRevLett.102.165005
• On electric field measurements in surface DBD discharge with nanosecond triggering
  
  • Allegraud Katia
  • Guaitella Olivier
  • Starikovskaia Svetlana
  • Rousseau Antoine
  , 2009.
• Properties of the whistler precursor emitted from a curved quasi-perpendicular shock: 2-D full particle simulation.
  
  • Stienlet J.
  • Lembège Bertrand
  • Savoini Philippe
  • Tscherning C. C.
  , 2009, 11, pp.9685. The few previous works dedicated to the whistler precursor analysis have been mainly based on the use of 1D simulations i.e. where the precursor propagates only along the shock normal. (Liewer et al., 1991) . More recently, curved shock propagating in a quasi-perpendicular angular range has been analyzed self-consistently with the use of 2D full particle simulations and has allowed to recover the main features of electron foreshock (Savoini et Lembege , 2003). The present work is based on similar simulations of a 2D curved shock but is focussed on the dynamics of the emitted whistler precursor. This precursor plays an important role in the global energy partition which takes place at and around the shock front (i.e. foreshock region) since it strongly interacts with incoming upstream plasma (mainly electrons). For a given Mach regime, main results show (i) the spatial upstream angular and radial extension where this precursor is emitted as compared with the electron foreshock region, (ii) the inhomogeneity of the precursor wavefronts , (iii) that the precursor globally propagates along the upstream magnetostatic field (and not only along the shock normal), (iv) its main features of damping versus emission in order to identify what main damping mechanisms are dominant (linear versus nonlinear Landau), and (v) its impact on electron dynamics. Results are compared with previous works obtained with 1D PIC simulation. The work is extended to different Mach regimes.
• Europlanet - Joining the European Planetary Research Information Service
  
  • Capria Maria Teresa
  • Chanteur Gérard
  • Schmidt Walter
  , 2009, 11, pp.9435. 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 model-ling teams. A central part of Europlanet RI is the "Integrated and Distributed Information Service" or Europlanet-IDIS which intends to provide easy Web-based access to information about scientists and teams working in related fields, observatories or laboratories with capabilities possibly beneficial to planetary research, modelling expertise useful for planetary science and observations from space-based, ground-based or laboratory measurements. As far as the type of data and their access methods allow, IDIS will provide Virtual Observatory (VO) like access to a variety of data from distributed sources and tools to compare and integrate this information to further data analysis and re-search. IDIS itself is providing a platform for information and data sharing and for data mining. It is structured as a network of thematic nodes each concentrating on a sub-set of research areas in planetary sciences. But the most important elements of IDIS and the whole Europlanet RI are the single scientists, institutes, laboratories, observatories and mission project teams. Without them the whole effort would remain an empty shell. How can an interested individual or team join this activity and what are the benefits to be expected from the related effort? The poster gives detailed answers to these questions. Here some highlights: 1. Locate from the Europlanet web pages (addresses see below) the thematic node best related to the own field of expertise. This might be more than one. 2. Define which services you want to offer to the community: just the contact address, field of competence, off-line access to data on request or even on-line searchable access to data to be integrated into the VO features of IDIS? Any combination and many more alternatives are possible. 3. Contact the staff of the selected node(s) to go through the details 4. The node's expert team will evaluate the information to ensure that it is compliant with the minimum requirements for Europlanet information providers like correct address, related field of competence, quality of data if any etc. 5. The new resource meta data (addresses, contents etc) will be added to the IDIS system including update of the search facilities 6. If data are offered for on-line access, the IDIS team will provide tools to generate a network-compatible generic interface. This one-time effort will make it possible to search the new data sets and combine them with related in-formation from other sources. Benefits for the information provider: - wide advertisement for the own resources and capabilities with increase in scientific references to the own activities and publications - new co-operation possibilities with so far unknown teams. Team exchange might be financially supported by other segments of the Europlanet RI - strong arguments for new funding applications and many more aspects List of contact web-sites: Technical node for support and management aspects: http://www.europlanet-idis.fi/ Planetary Surfaces and Interiors node: http://europlanet.dlr.de/ Planetary Plasma node: http://europlanet-plasmanode.oeaw.ac.at/ Planetary Atmospheres node: http://idis.ipsl.jussieu.fr/ Virtual Observatory Paris Data Centre: http://vo.obspm.fr/ Small Bodies and Dust node: http://www.ifsi-roma.inaf.it/europlanet
• Coupling of imaging and emission spectroscopy for MHCD discharge study
  
  • Lazzaroni Claudia
  • Chabert Pascal
  • Rousseau Antoine
  • Sadeghi N.
  , 2009.
• Polar cap boundary and the reconnection electric field
  
  • Aikio A.
  • Pitkänen T.
  • Kozlovsky A.
  • Amm Olaf
  • Fontaine Dominique
  • Hubert B.
  • Fazakerley A.
  • Tscherning C. C.
  , 2009, 11, pp.9311. Magnetic reconnection on the dayside magnetopause and in the nightside magnetotail are the main factors controlling the solar wind energy transfer into the magnetosphere and the ionosphere. Reconnection on the dayside magnetopause creates open magnetic flux and moves the polar cap boundary in the equatorward direction. Reconnection in the magnetotail, either at the distant neutral line or at the near-Earth neutral line during substorm conditions, closes magnetic field lines and moves the polar cap boundary into the poleward direction. The combined effect of dayside and nightside reconnection determines finally the dynamics of the polar cap boundary. A quantity that is related to changes in the amount of open magnetic flux is the reconnection electric field. In this talk, we will review some of the results obtained by using the EISCAT radar facility and supporting instruments (e.g. the MIRACLE magnetometers, the Cluster satellite, and global UVI imagers on Polar and IMAGE satellites) in estimating the motions of the polar cap boundary and the associated reconnection electric field. We have e.g. shown that the nightside reconnection close to substorm onset consists of a series of short-lived reconnection bursts and that isolated reconnection events may occur during the substorm recovery phase. We will also show, quantitatively for the first time to our knowledge, that intensifications in the local reconnection electric field have one-to-one correlation with the appearance of auroral poleward boundary intensifications (PBIs) within the same MLT location. These PBIs are observed by the Polar UVI instrument.