Publications

2014

Mars-Solar Wind Interaction: Coupling Between Hybrid, Ionospheric, Thermospheric and Exospheric Models
- Leblanc François
- Chaufray Jean-Yves
- Modolo Ronan
- Hess Sebastien
- Yagi M.
- Mancini M.
- Forget François
- Gonzalez-Galindo Francisco
- Lorenzato L.
- Mazelle Christian
- Chanteur Gérard
, 2014. The solar wind interaction with the Martian neutral envi- ronment is investigated by means of three dimensional hybrid magnetospheric simulations. In such formal- ism, ions have a kinetic description while electrons are treated as an inertialess fluid, ensuring the neutrality of the plasma and contributing to currents and pressure terms. This model has been successfully used to de- scribe the near ionized environment of Mars
Ignition of CH4:O2:Ar and n-C4H10:O2:Ar(N2) mixtures with initial temperatures between 650-950 K by a surface pulsed discharge
- Stepanyan S.A.
- Boumehdi M.A.
- Vanhove G.
- Desgroux Pascale
- Starikovskaia Svetlana
- Popov N.A.
, 2014. (10.2514/6.2014-0665)
DOI : 10.2514/6.2014-0665
Experimental and numerical study of fast gas heating and O atom production in a capillary nanosecond discharge
- Klochko A.V.
- Salmon A.
- Lemainque J.
- Popov N.A.
- Booth Jean-Paul
- Xiong Z.
- Kushner M.J.
- Starikovskaia Svetlana
, 2014, pp.2014-1030.
Adsorption, desorption and reactivity of O and N atoms on SiO2 surface
- Rousseau Antoine
, 2014.
New ferromagnetic core shapes for induction sensors
- Coillot Christophe
- Moutoussamy Joël
- Boda Mathieu
- Leroy Paul
Journal of Sensors and Sensor Systems, Copernicus Publ, 2014, pp.1-8. Induction sensors are used in a wide range of scientific and industrial applications. One way to improve these is rigorous modelling of the sensor combined with a low voltage and current input noise preamplifier aiming to optimize the whole induction magnetometer. In this paper, we explore another way, which consists in the use of original ferromagnetic core shapes of induction sensors, which bring substantial improvements. These new configurations are the cubic, orthogonal and coiled-core induction sensors. For each of them we give modelling elements and discuss their benefits and drawbacks with respect to a given noise-equivalent magnetic induction goal. Our discussion is supported by experimental results for the cubic and orthogonal configurations, while the coiled-core configuration remains open to experimental validation. The transposition of these induction sensor configurations to other magnetic sensors (fluxgate and giant magneto-impedance) is an exciting prospect of this work. (10.5194/jsss-3-1-2014)
DOI : 10.5194/jsss-3-1-2014
Multi Water Bag modelling of drift kinetic electrons and ions plasmas
- Morel Pierre
- Dreydemy Ghiro Florent
- Berionni Vincent
- Gürcan Özgür D.
, 2014.
Spatial Propagation of Turbulence and Formation of Mesoscopic Structures in Plasma Turbulence
- Dif-Pradalier Guilhem
- Ghendrih Ph.
- Diamond P.H.
- Garbet X.
- Grandgirard V.
- Norscini C.
- Palermo F.
- Sarazin Y.
- Abiteboul J.
- Dong Yue
- Gürcan Özgür D.
- Hennequin Pascale
- Morel Pierre
- Vermare Laure
- Kosuga Y.
, 2014.
On the origin of falling-tone chorus elements in Earth's inner magnetosphere
- Breuillard H
- Agapitov O
- Artemyev A
- Krasnoselskikh V
- Le Contel Olivier
- Cully C. M.
- Angelopoulos V
- Zaliznyak Y
- Rolland G
Annales Geophysicae, European Geosciences Union, 2014, 32, pp.1477-1485. Generation of extremely/very low frequency (ELF/VLF) chorus waves in Earth's inner magnetosphere has received increased attention recently because of their significance for radiation belt dynamics. Though past theoretical and numerical models have demonstrated how rising-tone chorus elements are produced, falling-tone chorus element generation has yet to be explained. Our new model proposes that weak-amplitude falling-tone chorus elements can be generated by magnetospheric reflection of rising-tone elements. Using ray tracing in a realistic plasma model of the inner magnetosphere, we demonstrate that rising-tone elements originating at the magnetic equator propagate to higher latitudes. Upon reflection there, they propagate to lower L-shells and turn into oblique falling tones of reduced power, frequency, and bandwidth relative to their progenitor rising tones. Our results are in good agreement with comprehensive statistical studies of such waves, notably using magnetic field measurements from THEMIS (Time History of Events and Macroscale Interactions during Substorms) spacecraft. Thus, we conclude that the proposed mechanism can be responsible for the generation of weak-amplitude falling-tone chorus emissions. (10.5194/angeo-32-1477-2014)
DOI : 10.5194/angeo-32-1477-2014
Radiation sources with planar wire arrays and planar foils for inertial confinement fusion and high energy density physics research
- Kantsyrev Viktor L.
- Chuvatin Alexandre S.
- Safronova Alla S.
- Rudakov Leonid I.
- Esaulov A. A.
- Velikovich A. L.
- Shrestha Ishor
- Astanovitsky A.
- Osborne Glenn C.
- Shlyaptseva V. V.
- Weller Michael E.
- Keim S.
- Stafford A.
- Cooper M. C.
Physics of Plasmas, American Institute of Physics, 2014, 21 (03), pp.031204. This article reports on the joint success of two independent lines of research, each of them being a multi-year international effort. One of these is the development of innovative sources, such as planar wire arrays (PWAs). PWAs turned out to be a prolific radiator, which act mainly as a resistor, even though the physical mechanism of efficient magnetic energy conversion into radiation still remains unclear. We review the results of our extensive studies of PWAs. We also report the new results of the experimental comparison PWAs with planar foil liners (another promising alternative to wire array loads at multi-mega-ampere generators). Pioneered at UNR, the PWA Z-pinch loads have later been tested at the Sandia National Laboratories (SNL) on the Saturn generator, on GIT-12 machine in Russia, and on the QiangGuang-1 generator in China, always successfully. Another of these is the drastic improvement in energy efficiency of pulsed-power systems, which started in early 1980s with Zucker's experiments at Naval Research Laboratory (NRL). Successful continuation of this approach was the Load Current Multiplier (LCM) proposed by Chuvatin in collaboration with Rudakov and Weber from NRL. The 100 ns LCM was integrated into the Zebra generator, which almost doubled the plasma load current, from 0.9 to 1.7 MA. The two above-mentioned innovative approaches were used in combination to produce a new compact hohlraum radiation source for ICF, as jointly proposed by SNL and UNR [Jones et al., Phys. Rev. Lett. 104, 125001 (2010)]. The first successful proof-of-the-principle experimental implementation of new hohlraum concept at university-scale generator Zebra/LCM is demonstrated. A numerical simulation capability with VisRaD code (from PRISM Co.) established at UNR allowed for the study of hohlraum coupling physics and provides the possibility of optimization of a new hohlraum. Future studies are discussed. (10.1063/1.4865367)
DOI : 10.1063/1.4865367
The FIELDS Instrument Suite on MMS: Scientific Objectives, Measurements, and Data Products
- Torbert R. B.
- Russell C. T.
- Magnes W.
- Ergun R. E.
- Lindqvist P.-A.
- Le Contel Olivier
- Vaith H.
- Macri J.
- Myers S.
- Rau D.
- Needell J.
- King B.
- Granoff M.
- Chutter M.
- Dors I.
- Olsson G.
- Khotyaintsev Y. V.
- Eriksson A.
- Kletzing C. A.
- Bounds S.
- Anderson B.
- Baumjohann W.
- Steller M.
- Bromund K.
- Le G.
- Nakamura R.
- Strangeway R. J.
- Leinweber H. K.
- Tucker S.
- Westfall J.
- Fischer D.
- Plaschke F.
- Porter J.
- Lappalainen K.
Space Science Reviews, Springer Verlag, 2014, pp.1-31. Not Available (10.1007/s11214-014-0109-8)
DOI : 10.1007/s11214-014-0109-8
Complete multi-field characterization of the geodesic acoustic mode in the TCV tokamak
- de Meijere C. A.
- Coda S.
- Huang Z.
- Vermare Laure
- Vernay T.
- Vuille V.
- Brunner Stephan
- Dominski J.
- Hennequin Pascale
- Kraemer-Flecken A.
- Merlo G.
- Porte L.
- Villard Laurent
Plasma Physics and Controlled Fusion, IOP Publishing, 2014, 56 (7), pp.072001. The geodesic acoustic mode (GAM) is a coherently oscillating zonal flow that may regulate turbulence in toroidal plasmas. Uniquely, the complete poloidal and toroidal structure of the magnetic component of the turbulence-driven GAM has been mapped in the TCV tokamak. Radially localized measurements of the fluctuating density, ECE radiative temperature and poloidal flow show that the GAM is a fully coherent, radially propagating wave. These observations are consistent with electrostatic, gyrokinetic simulations. (10.1088/0741-3335/56/7/072001)
DOI : 10.1088/0741-3335/56/7/072001
Turbulence elasticity-A new mechanism for transport barrier dynamics
- Guo Z. B.
- Diamond P.H.
- Kosuga Y.
- Gürcan Özgür D.
Physics of Plasmas, American Institute of Physics, 2014, 21 (9). We present a new, unified model of transport barrier formation in ``elastic'' drift wave-zonal flow (DW-ZF) turbulence. A new physical quantity-the delay time (i.e., the mixing time for the DW turbulence)-is demonstrated to parameterize each stage of the transport barrier formation. Quantitative predictions for the onset of limit-cycle-oscillation (LCO) among DW and ZF intensities (also denoted as I-mode) and I-mode to high-confinement mode (H-mode) transition are also given. The LCO occurs when the ZF shearing rate (vertical bar (ZF)'vertical bar) enters the regime Delta omega(k) < vertical bar < V >(ZF)'vertical bar < tau(-1)(cr), where Delta omega(k) is the local turbulence decorrelation rate and tau(cr) is the threshold delay time. In the basic predator-prey feedback system, tau(cr) is also derived. The I-H transition occurs when vertical bar < V >(ExB)'vertical bar > tau(-1)(cr), where the mean E x B shear flow driven by ion pressure ``locks'' the DW-ZF system to the H-mode by reducing the delay time below the threshold value. (C) 2014 AIP Publishing LLC. (10.1063/1.4894695)
DOI : 10.1063/1.4894695
Ion flux asymmetry in radiofrequency capacitively-coupled plasmas excited by sawtooth-like waveforms
- Bruneau Bastien
- Novikova T.
- Lafleur Trevor
- Booth Jean-Paul
- Johnson E.V.
Plasma Sources Science and Technology, IOP Publishing, 2014, 23 (6), pp.065010. Using particle-in-cell simulations, we predict that it is possible to obtain a significant difference between the ion flux to the powered electrode and that to the grounded electrode?with about 50% higher ion flux on one electrode?in a geometrically symmetric, radiofrequency capacitively-coupled plasma reactor by applying a non-sinusoidal, ?Tailored? voltage waveform. This sawtooth-like waveform presents different rising and falling slopes over one cycle. We show that this effect is due to differing plasma sheath motion in front of each electrode, which induces a higher ionization rate in front of the electrode which has the fastest positive rising voltage. Together with the higher ion flux comes a lower voltage drop across the sheath, and therefore a reduced maximum ion bombardment energy; a result in contrast to typical process control mechanisms. (10.1088/0963-0252/23/6/065010)
DOI : 10.1088/0963-0252/23/6/065010
Plasma-assisted ignition and combustion: nanosecond discharges and development of kinetic mechanisms
- Starikovskaia Svetlana
Journal of Physics D: Applied Physics, IOP Publishing, 2014, 47 (35), pp.353001 (34pp). This review covers the results obtained in the period 20062014 in the field of plasma-assisted combustion, and in particular the results on ignition and combustion triggered or sustained by pulsed nanosecond discharges in different geometries. Some benefits of pulsed high voltage discharges for kinetic study and for applications are demonstrated. The necessity of and the possibility of building a particular kinetic mechanism of plasma-assisted ignition and combustion are discussed. The most sensitive regions of parameters for plasmacombustion kinetic mechanisms are selected. A map of the pressure and temperature parameters (PT diagram) is suggested, to unify the available data on ignition delay times, ignition lengths and densities of intermediate species reported by different authors. (10.1088/0022-3727/47/35/353001)
DOI : 10.1088/0022-3727/47/35/353001
The influence of the geometry and electrical characteristics on the formation of the atmospheric pressure plasma jet
- Sobota Ana
- Guaitella Olivier
- Rousseau Antoine
Plasma Sources Science and Technology, IOP Publishing, 2014, 23, pp.025016. An extensive electrical study was performed on a coaxial geometry atmospheric pressure plasma jet source in helium, driven by 30 kHz sine voltage. Two modes of operation were observed, a highly reproducible low-power mode that features the emission of one plasma bullet per voltage period and an erratic high-power mode in which micro-discharges appear around the grounded electrode. The minimum of power transfer efficiency corresponds to the transition between the two modes. Effective capacitance was identified as a varying property influenced by the discharge and the dissipated power. The charge carried by plasma bullets was found to be a small fraction of charge produced in the source irrespective of input power and configuration of the grounded electrode. The biggest part of the produced charge stays localized in the plasma source and below the grounded electrode, in the range 1.23.3 nC for ground length of 38 mm. (10.1088/0963-0252/23/2/025016)
DOI : 10.1088/0963-0252/23/2/025016
What is the size of a floating sheath?
- Chabert Pascal
Plasma Sources Science and Technology, IOP Publishing, 2014, 23 (6), pp.065042. The size of the positive space charge sheath that forms in front of an object immersed in a plasma and not dc-connected to ground with an external circuit (a floating sheath) is calculated numerically. If the sheath edge is defined as the position at which the ion fluid speed equals the Bohm speed, it is shown that the sheath size varies significantly with the discharge parameters, typically from s float ≈ 7 λ Des to s float ≈ 14 λ Des , where s float is the floating sheath size and λ Des is the Debye length at the sheath edge. However, if the sheath edge is defined as a significant departure from quasi-neutrality, then the floating sheath size is almost independent of the discharge parameters and may be approximated by s float ≈ 5 λ Des . (10.1088/0963-0252/23/6/065042)
DOI : 10.1088/0963-0252/23/6/065042
Circulation of Heavy Ions and Their Dynamical Effects in the Magnetosphere: Recent Observations and Models
- Kronberg E. A.
- Ashour-Abdalla M.
- Dandouras I.
- Delcourt Dominique C.
- Grigorenko E. E.
- Kistler L. M.
- Kuzichev I. V.
- Liao J.
- Maggiolo R.
- Malova H. V.
- Orlova K. G.
- Peroomian V.
- Shklyar D. R.
- Shprits Y. Y.
- Welling D. T.
- Zelenyi L. M.
Space Science Reviews, Springer Verlag, 2014, 184 (1-4), pp.173-235. Knowledge of the ion composition in the near-Earths magnetosphere and plasma sheet is essential for the understanding of magnetospheric processes and instabilities. The presence of heavy ions of ionospheric origin in the magnetosphere, in particular oxygen (O ), influences the plasma sheet bulk properties, current sheet (CS) thickness and its structure. It affects reconnection rates and the formation of Kelvin-Helmholtz instabilities. This has profound consequences for the global magnetospheric dynamics, including geomagnetic storms and substorm-like events. The formation and demise of the ring current and the radiation belts are also dependent on the presence of heavy ions. In this review we cover recent advances in observations and models of the circulation of heavy ions in the magnetosphere, considering sources, transport, acceleration, bulk properties, and the influence on the magnetospheric dynamics. We identify important open questions and promising avenues for future research. (10.1007/s11214-014-0104-0)
DOI : 10.1007/s11214-014-0104-0
Evolution of Turbulence in the Expanding Solar Wind, a Numerical Study
- Dong Yue
- Verdini Andrea
- Grappin Roland
The Astrophysical Journal, American Astronomical Society, 2014, 793, pp.118. We study the evolution of turbulence in the solar wind by solving numerically the full three-dimensional (3D) magnetohydrodynamic (MHD) equations embedded in a radial mean wind. The corresponding equations (expanding box model or EBM) have been considered earlier but never integrated in 3D simulations. Here, we follow the development of turbulence from 0.2 AU up to about 1.5 AU. Starting with isotropic spectra scaling as k -1, we observe a steepening toward a k -5/3 scaling in the middle of the wave number range and formation of spectral anisotropies. The advection of a plasma volume by the expanding solar wind causes a non-trivial stretching of the volume in directions transverse to radial and the selective decay of the components of velocity and magnetic fluctuations. These two effects combine to yield the following results. (1) Spectral anisotropy: gyrotropy is broken, and the radial wave vectors have most of the power. (2) Coherent structures: radial streams emerge that resemble the observed microjets. (3) Energy spectra per component: they show an ordering in good agreement with the one observed in the solar wind at 1 AU. The latter point includes a global dominance of the magnetic energy over kinetic energy in the inertial and f -1 range and a dominance of the perpendicular-to-the-radial components over the radial components in the inertial range. We conclude that many of the above properties are the result of evolution during transport in the heliosphere, and not just the remnant of the initial turbulence close to the Sun. (10.1088/0004-637X/793/2/118)
DOI : 10.1088/0004-637X/793/2/118
Investigation of drift velocity effects on the EDGE and SOL transport.
- Leybros Robin
- Bufferand H.
- Ciraolo G.
- Fedorczak N.
- Ghendrih Ph.
- Hennequin Pascale
- Marandet Y.
- Serre E.
- Schwander F.
- Tamain P.
, 2014.
Plasma composition and ion acceleration in the PEGASES thruster
- Renaud D.
- Mazouffre S.
- Aanesland Ane
Space Propulsion, 2014 (2969109).
Ionospheric disturbance dynamo associated to a coronal hole: Case study of 5-10 April 2010
- Fathy Ibrahim
- Amory-Mazaudier Christine
- Fathy A.
- Mahrous A. M.
- Yumoto K.
- Ghamry E.
Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2014, 119 (5), pp.4120–4133. In this paper we study the planetary magnetic disturbance during the magnetic storm occurring on 5 April 2010 associated with high-speed solar wind stream due to a coronal hole following a coronal mass ejection. We separate the magnetic disturbance associated to the ionospheric disturbance dynamo (Ddyn) from the magnetic disturbance associated to the prompt penetration of magnetospheric electric field (DP2). This event exhibits different responses of ionospheric disturbance dynamo in the different longitude sectors (European-African, Asian, and American). The strongest effect is observed in the European-African sector. The Ddyn disturbance reduces the amplitude of the daytime H component at low latitudes during four consecutive days in agreement with the Blanc and Richmond's model of ionospheric disturbance dynamo. The amplitude of Ddyn decreased with time during the 4 days. We discuss its diverse worldwide effects. The observed signature of magnetic disturbance process in specific longitude sector is strongly dependent on which Earth's side faces the magnetic storms (i.e., there is a different response depending on which longitude sector is at noon when the SSC hits). Finally, we determined an average period of 22 h for Ddyn using wavelet analysis. (10.1002/2013JA019510)
DOI : 10.1002/2013JA019510
The double well mass filter
- Gueroult R
- Fisch Nathaniel J.
- Rax Jean-Marcel
Physics of Plasmas, American Institute of Physics, 2014, 21 (2), pp.020701. Various mass filter concepts based on rotating plasmas have been suggested with the specific purpose of nuclear waste remediation. We report on a new rotating mass filter combining radial separation with axial extraction. The radial separation of the masses is the result of a “double-well” in effective radial potential in rotating plasma with a sheared rotation profile. (10.1063/1.4864325)
DOI : 10.1063/1.4864325
Surface deactivation of vibrationally excited N2 studied using infrared titration combined with quantum cascade laser absorption spectroscopy
- Marinov Daniil
- Lopatik D.
- Guaitella Olivier
- Ionikh Y.
- Röpcke J.
- Rousseau Antoine
Journal of Physics D: Applied Physics, IOP Publishing, 2014, 47 (1), pp.015203. The wall de-excitation probability of vibrationally excited nitrogen molecules was determined using infrared (IR) titration with CO, CO 2 and N 2 O. Gas mixtures of N 2 with 0.05?0.5% of CO (CO 2 or N 2 O) were excited by a pulsed dc discharge at p = 133 Pa in a cylindrical discharge tube. During the afterglow, the vibrational relaxation of titrating molecules was monitored in situ with quantum cascade laser absorption spectroscopy. The value of was deduced from measured vibrational relaxation times using a model of vibrational kinetics in N 2 . It was found that adsorption of IR tracers on the surface may increase the value of by a factor up to two, depending on the molecule and the surface material. It was demonstrated that N 2 O is the most inert and reliable tracer and it was used for the determination of on silica, Pyrex, TiO 2 , Al 2 O 3 and anodized aluminum. Pretreatment of the silica surface by low-pressure plasma was found to have a strong effect on the vibrational de-excitation. Values of measured after O 2 , Ar and N 2 plasma pretreatment of the same silica discharge tube were 5.7 × 10 ?4 , 8.2 × 10 ?4 and 11 × 10 ?4 , respectively. This study clearly demonstrates that the presence of adsorbed atoms and molecules on the surface may significantly alter the value of . (10.1088/0022-3727/47/1/015203)
DOI : 10.1088/0022-3727/47/1/015203
Study of gas heating mechanisms in millisecond pulsed discharges and afterglows in air at low pressures
- Pintassilgo C.D.
- Guerra V.
- Guaitella Olivier
- Rousseau Antoine
Plasma Sources Science and Technology, IOP Publishing, 2014, 23, pp.025006. A self-consistent model is developed to study the temporal variation of the gas temperature in millisecond single dc pulsed discharges and their afterglows in air-like mixtures (N220%O2) at low pressures. The model is based on the solutions to the time-dependent gas thermal balance equation, under the assumption of a parabolic gas temperature profile across the discharge tube, coupled to the electron, vibrational and chemical kinetics. Modelling results provide a satisfactory explanation for recently published time-resolved experimental data for the gas temperature in a 5 ms pulsed air plasma with a current of 150mA and the corresponding afterglow at a pressure of 133 Pa (1 Torr). It is shown that the main heating mechanisms during the first millisecond of the pulse come predominantly from O2 dissociation by electron impact through the pre-dissociative excited state O2(B 3− u ) and the quenching of nitrogen electronically excited states N2(A 3 u , B 3 g, a 1− u , a 1 g, w 1u) by O2, agreeing with other studies on fast gas heating in air plasmas. As the pulse duration increases, other gas heating sources become important, namely VT N2O energy exchanges, recombination of oxygen atoms at the wall, N2(A) quenching by O(3P) and reaction N(4S) NO(X) → N2(X, v ∼3) O, contributing altogether to an additional smooth increase in the gas temperature until the end of the pulse. In the first instants of the early afterglow, the gas temperature decreases very rapidly as a consequence of the minor role played by electronic collisions and due to a fast decay of N2 electronic states. For afterglow times up to 10 ms, the gas temperature continues to decrease, following the time-dependent kinetics of [N2(X,v)], [N(4S)], [O(3P)] and [NO(X)]. Sensitivity of the model to different input parameters such as thermal accommodation coefficient and probabilities for atomic recombination at the wall are reported. (10.1088/0963-0252/23/2/025006)
DOI : 10.1088/0963-0252/23/2/025006
Ambipolar and non-ambipolar diffusion in an rf plasma source containing a magnetic filter
- Lafleur Trevor
- Aanesland Ane
Physics of Plasmas, American Institute of Physics, 2014, 21, pp.063510. By placing a magnetic filter across a rectangular plasma source (closed at one end with a ceramic plate and an rf antenna, and terminated at the opposite end by a grounded grid), we experimentally investigate the effect of conducting and insulating source walls on the nature of the plasma diffusion phenomena. The use of a magnetic filter creates a unique plasma, characterized by a high upstream electron temperature (Teu∼5 eV) near the rf antenna and a low downstream electron temperature (Ted∼1 eV) near the grid, which more clearly demonstrates the role of the source wall materials. For conducting walls a net ion current to ground is measured on the grid, and the plasma potential is determined by a mean electron temperature within the source. For insulating walls the plasma potential is determined by the downstream electron temperature (i.e., Vp∼5.2Ted in argon), and the net current to the grid is exactly zero. Furthermore, by inserting a small additional upstream conductor (that can be made floating or grounded through an external circuit switch), we demonstrate that the plasma potential can be controlled and set to a low (Vp∼5.2Ted), or high (Vp∼5.2Teu) value. (10.1063/1.4885109)
DOI : 10.1063/1.4885109

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