Publications

2010

• Plasmas froids
  
  • Booth Jean-Paul
  • Chabert Pascal
  Flash X - La revue scientifique de l'Ecole polytechnique, Ecole polytechnique, 2010, 12, pp.3-5. ISSN : 1775-0385
• Bilan et Perspective 2006 - 2009, Programme National Soleil Terre
  
  • Fontaine Dominique
  • Vilmer N.
  , 2010.
• Plasma assisted ignition and combustion
  
  • Starikovskaia Svetlana
  • Starikovskii A.Yu.
  , 2010, pp.71-93.
• Planar Wire-Array Z-Pinch Implosion Dynamics and X-Ray Scaling at Multiple-MA Drive Currents for a Compact Multisource Hohlraum Configuration
  
  • Jones B.
  • Ampleford D. J.
  • Vesey R. A.
  • Cuneo Michael E.
  • Coverdale C. A.
  • Waisman E. M.
  • Jones M. C.
  • Fowler W. E.
  • Stygar W. A.
  • Serrano J. D.
  • Vigil M. P.
  • Esaulov A. A.
  • Kantsyrev Viktor L.
  • Safronova Alla S.
  • Williamson Kenneth M.
  • Chuvatin Alexandre S.
  • Rudakov Leonid I.
  Physical Review Letters, American Physical Society, 2010, 104 (12), pp.125001. An indirect drive configuration is proposed wherein multiple compact Z-pinch x-ray sources surround a secondary hohlraum. Planar compact wire arrays allow reduced primary hohlraum surface area compared to cylindrical loads. Implosions of planar arrays are studied at up to 15 TW x-ray power on Saturn with radiated yields exceeding the calculated kinetic energy, suggesting other heating paths. X-ray power and yield scaling studied from 16 MA motivates viewfactor modeling of four 6-MA planar arrays producing 90 eV radiation temperature in a secondary hohlraum. (10.1103/PhysRevLett.104.125001)
  DOI : 10.1103/PhysRevLett.104.125001
• Nonlinear fan instability of electromagnetic waves
  
  • Krafft C.
  • Volokitin A.
  Physics of Plasmas, American Institute of Physics, 2010, 17, pp.102303. This paper studies the linear and nonlinear stages of the fan instability, considering electromagnetic waves of the whistler frequency range interacting resonantly with energetic electron fluxes in magnetized plasmas. The main attention is paid to determine the wave-particle interaction processes that can lead to the excitation of intense electromagnetic waves by nonequilibrium particle distributions involving suprathermal tails, and to explain under what conditions and through what mechanisms they can occur, develop, and saturate. This paper presents and discusses two main processes: (i) the linear fan instability and (ii) the nonlinear process of dynamical resonance merging, which can significantly amplify the energy carried by linearly destabilized waves after they saturate due to particle trapping. This study consists of (i) determining analytically and numerically, for parameters typical of space and laboratory plasmas, the linear growth rates of whistlers excited by suprathermal particle fluxes through the fan instability, as well as the corresponding thresholds and the physical conditions at which the instability can appear, (ii) building a theoretical self-consistent 3D model and a related numerical code for describing the nonlinear evolution of the wave-particle system, and (iii) performing numerical simulations to reveal and characterize the nonlinear amplification process at work, its conditions of development, and its consequences, notably in terms of electromagnetic wave radiation. The simulations show that when the waves have reached sufficient energy levels owing to the linear fan instability, they saturate by trapping particles and due to the complex dynamics of these particles in the electromagnetic fields, the resonant velocities' domains of the waves overlap and merge, meanwhile a strong increase of the wave energy occurs. (10.1063/1.3479829)
  DOI : 10.1063/1.3479829
• Modelling of an afterglow plasma in air produced by a pulsed discharge
  
  • Pintassilgo C.D.
  • Guerra V.
  • Guaitella Olivier
  • Rousseau Antoine
  Plasma Sources Science and Technology, IOP Publishing, 2010, 19, pp.055001. A kinetic model is developed to study the afterglow plasma of a pulsed discharge in air. This model includes a detailed analysis of the temporal evolution of heavy species during the pulse, followed by their relaxation in the afterglow. The predicted results are compared with two experimental sets performed in the time afterglow of a pulsed discharge in N220%O2 at a pressure p = 133 Pa involving the measurements of (i) N2(B) and N2(C) fluorescences for a discharge current I = 40 mA and a pulse duration τ = 200 µs and 10 ms, together with (ii) the absolute concentration of NO(X) for I = 40 and 80 mA with τ varying from 1 to 4 ms. The results of the model agree reasonably well with the measurements of N2(B) and N2(C) decays. It is shown that under these experimental conditions, N2(B) is always populated mainly via the process N2(A) N2(X, 5 ≤ v ≤ 14) → N2(B) N2(X, v = 0), while the relaxation of N2(C) is dominated by the pooling reaction N2(A) N2(A) → N2(C) N2(X, v = 0). An almost constant concentration of NO(X) is experimentally observed until the remote afterglow, but the present model is only capable of predicting the same order of magnitude for afterglow times t 0.05 s. Several hypotheses are discussed and advanced in order to explain this discrepancy. (10.1088/0963-0252/19/5/055001)
  DOI : 10.1088/0963-0252/19/5/055001
• Quantum Cascade Laser Absorption Spectroscopy - a New Method to Study Molecular Plasma Components
  
  • Röpcke J.
  • Glitsch S.
  • Davies P.B.
  • Hempel F.
  • Lang N.
  • Rousseau Antoine
  • Wege S.
  • Welzel S.
  Journal of Physics: Conference Series, IOP Science, 2010, 227, pp.012005. The recent development of quantum cascade lasers (QCLs) offers an attractive new option for the monitoring and control of industrial plasma processes and for trace-gas analysis as well as for highly time-resolved studies on the kinetics of plasma processes. The contribution reviews selected examples of the application of QCLs for infrared absorption studies in basic research and for plasma monitoring and control in industry. (10.1088/1742-6596/227/1/012005)
  DOI : 10.1088/1742-6596/227/1/012005
• RPWS_ViToS
  
  • Piberne Rodrigue
  • Canu Patrick
  , 2010. RPWS_ViToS is an IDL software for data processing and visualization of the RPW instrument of the Cassini mission.
• Scientific objectives and instrumentation of Mercury Plasma Particle Experiment (MPPE) onboard MMO
  
  • Saito Y.
  • Sauvaud J.-A.
  • Hirahara M.
  • Barabash S.
  • Delcourt Dominique C.
  • Takashima T.
  • Asamura K.
  Planetary and Space Science, Elsevier, 2010, 58 (1-2), pp.182-200. Mercury is one of the least explored planets in our solar system. Until the recent flyby of Mercury by MESSENGER, no spacecraft had visited Mercury since Mariner 10 made three flybys: two in 1974 and one in 1975. In order to elucidate the detailed plasma structure and dynamics around Mercury, an orbiter BepiColombo MMO (Mercury Magnetospheric Orbiter) is planned to be launched in 2013 as a joint mission between ESA and ISAS/JAXA. Mercury Plasma Particle Experiment (MPPE) was proposed in order to investigate the plasma/particle environment around Mercury. MPPE is a comprehensive instrument package for plasma, high-energy particle and energetic neutral atom measurements. It consists of seven sensors: two Mercury electron analyzers (MEA1 and MEA2), Mercury ion analyzer (MIA), Mercury mass spectrum analyzer (MSA), high-energy particle instrument for electron (HEP-ele), high-energy particle instrument for ion (HEP-ion), and energetic neutrals analyzer (ENA). Since comprehensive full three-dimensional simultaneous measurements of low to high-energy ions and electrons around Mercury as well as measurements of energetic neutral atoms will not be realized before BepiColombo/MMO's arrival at Mercury, it is expected that many unresolved problems concerning the Mercury magnetosphere will be elucidated by the MPPE observation. (10.1016/j.pss.2008.06.003)
  DOI : 10.1016/j.pss.2008.06.003
• Observations multi-satellitaires de l'interaction Vent Solaire - Magnétosphère
  
  • Sahraoui Fouad
  • Cornilleau-Wehrlin Nicole
  Flash X - La revue scientifique de l'Ecole polytechnique, Ecole polytechnique, 2010, 12, pp.33-34. ISSN : 1775-0385
• Observation and theoretical modeling of electron scale solar wind turbulence
  
  • Sahraoui Fouad
  • Belmont Gérard
  • Goldstein M. L.
  • Kiyani K. H.
  • Robert Patrick
  • Canu Patrick
  , 2010.
• Plasmas de Fusion Magnétique
  
  • Hennequin Pascale
  Flash X - La revue scientifique de l'Ecole polytechnique, Ecole polytechnique, 2010, 12, pp.25-26. ISSN : 1775-0385
• Operation of a load current multiplier on a nanosecond mega-ampere pulse forming line generator
  
  • Chuvatin Alexandre S.
  • Kantsyrev Viktor L.
  • Rudakov Leonid I.
  • Cuneo Michael E.
  • Astanovitskiy A. L.
  • Presura Radu
  • Safronova Alla S.
  • Cline W.
  • Williamson Kenneth M.
  • Shrestha Ishor
  • Osborne Glenn C.
  • Le Galloudec B.
  • Nalajala Vidya
  • Pointon T. D.
  • Mikkelson K. A.
  Physical Review Special Topics: Accelerators and Beams, American Physical Society, 2010, 13 (1), pp.010401. We investigate the operation of a load current multiplier (LCM) on a pulse-forming-line nanosecond pulse-power generator. Potential benefits of using the LCM technique on such generators are studied analytically for a simplified case. A concrete LCM design on the Zebra accelerator (1.9 Ohm, ∼1  MA, 100 ns) is described. This design is demonstrated experimentally with high-voltage power pulses having a rise time of dozens of nanoseconds. Higher currents and magnetic energies were observed in constant-inductance solid-state loads when a better generator-to-load energy coupling was achieved. The load current on Zebra was increased from the nominal 0.80.9 MA up to about 1.6 MA. This result was obtained without modifying the generator energetics or architecture and it is in good agreement with the presented numerical simulations. Validation of the LCM technique at a nanosecond time scale is of importance for the high-energy-density physics research. (10.1103/PhysRevSTAB.13.010401)
  DOI : 10.1103/PhysRevSTAB.13.010401
• A simple model of intrinsic rotation in high confinement regime tokamak plasmas
  
  • Gürcan Özgür D.
  • Diamond P.H.
  • Mcdevitt C.J.
  • Hahm T.S.
  Physics of Plasmas, American Institute of Physics, 2010, 17, pp.032509. A simple unified model of intrinsic rotation and momentum transport in high confinement regime (H-mode) tokamak plasmas is presented. Motivated by the common dynamics of the onset of intrinsic rotation and the L-H transition, this simple model combines E×B shear-driven residual stress in the pedestal with a turbulent equipartition pinch to yield rotation profiles. The residual stress is the primary mechanism for buildup of intrinsic rotation in the H-mode pedestal, while the pinch drives on-axis peaking of rotation profiles. Analytical estimates for pedestal flow velocities are given in terms of the pedestal width, the pedestal height, and various model parameters. The predicted scaling of the toroidal flow speed with pedestal width is found to be consistent with the International Tokamak Physics Activity database global scaling of the flow speed on-axis with the total plasma stored energy. (10.1063/1.3339909)
  DOI : 10.1063/1.3339909
• Wave-particle interactions in the equatorial source region of whistler-mode emissions
  
  • Santolík Ondrej
  • Gurnett D. A.
  • Pickett J. S.
  • Grimald S.
  • Décréau Pierrette
  • Parrot Michel
  • Cornilleau-Wehrlin Nicole
  • El-Lemdani Mazouz Farida
  • Schriver D.
  • Meredith N. P.
  • Fazakerley A.
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2010, 115 (A8). Wave-particle interactions can play a key role in the process of transfer of energy between different electron populations in the outer Van Allen radiation belt. We present a case study of wave-particle interactions in the equatorial source region of whistler-mode emissions. We select measurements of the Cluster spacecraft when these emissions are observed in the form of random hiss with only occasional discrete chorus wave packets, and where the wave propagation properties are very similar to previously analyzed cases of whistler-mode chorus. We observe a positive divergence of the Poynting flux at minima of the magnetic field modulus along the magnetic field lines, indicating the central position of the source. In this region we perform a linear stability analysis based on the locally measured electron phase space densities. We find two unstable electron populations. The first of them consists of energy-dispersed and highly anisotropic injected electrons at energies of a few hundreds eV to a few keV, with the perpendicular temperature more than 10 times higher than the parallel temperature with respect to the magnetic field line. Another unstable population is formed by trapped electrons at energies above 10 keV. We show that the injected electrons at lower energies can be responsible for a part of the waves that propagate obliquely at frequencies above one half of the electron cyclotron frequency. Our model of the trapped electrons at higher energies gives insufficient growth of the waves below one half of the electron cyclotron frequency and a nonlinear generation mechanism might be necessary to explain their presence even in this simple case. (10.1029/2009JA015218)
  DOI : 10.1029/2009JA015218
• Non adiabatic electron behavior through a supercritical perpendicular collisionless shock: Impact of the shock front turbulence
  
  • Savoini Philippe
  • Lembège Bertrand
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2010, 115 (A11), pp.A11103. Adiabatic and nonadiabatic electrons transmitted through a supercritical perpendicular shock wave are analyzed with the help of test particle simulations based on field components issued from 2 − D full-particle simulation. A previous analysis (Savoini et al., 2005) based on 1 − D shock profile, including mainly a ramp (no apparent foot) and defined at a fixed time, has identified three distinct electron populations: adiabatic, overadiabatic, and underadiabatic, respectively, identified by μds/μus ≈ 1, >1 and <1, where μus and μds are the magnetic momenta in the upstream and downstream regions. Presently, this study is extended by investigating the impact of the time evolution of 2 − D shock front dynamics on these three populations. Analysis of individual time particle trajectories is performed and completed by statistics based on the use of different upstream velocity distributions (spherical shell of radius vshell and a Maxwellian with thermal velocity vthe). In all statistics, the three electron populations are clearly recovered. Two types of shock front nonstationarity are analyzed. First, the impact of the nonstationarity along the shock normal (due to the front self-reformation only) strongly depends on the values of vshell or vthe. For low values, the percentages of adiabatic and overadiabatic electrons are almost comparable but become anticorrelated under the filtering impact of the self-reformation; the percentage of the underadiabatic population remains almost unchanged. In contrast, for large values, this impact becomes negligible and the adiabatic population alone becomes dominant. Second, when 2 − D nonstationarity effects along the shock front (moving rippling) are fully included, all three populations are strongly diffused, leading to a larger heating; the overadiabatic population becomes largely dominant (and even larger than the adiabatic one) and mainly contributes to the energy spectrum. (10.1029/2010JA015381)
  DOI : 10.1029/2010JA015381
• Chorus source region localization in the Earth's outer magnetosphere using THEMIS measurements
  
  • Agapitov O
  • Krasnoselskikh V
  • Zaliznyak Yu
  • Angelopoulos V
  • Le Contel Olivier
  • Rolland G
  Annales Geophysicae, European Geosciences Union, 2010, 28, pp.1377–1386. Discrete ELF/VLF chorus emissions, the most intense electromagnetic plasma waves observed in the Earth's radiation belts and outer magnetosphere, are thought to propagate roughly along magnetic field lines from a localized source region near the magnetic equator towards the magnetic poles. THEMIS project Electric Field Instrument (EFI) and Search Coil Magnetometer (SCM) measurements were used to determine the spatial scale of the chorus source lo-calization region on the day side of the Earth's outer magne-tosphere. We present simultaneous observations of the same chorus elements registered onboard several THEMIS spacecraft in 2007 when all the spacecraft were in the same orbit. Discrete chorus elements were observed at 0.15–0.25 of the local electron gyrofrequency, which is typical for the outer magnetosphere. We evaluated the Poynting flux and wave vector distribution and obtained chorus wave packet quasi-parallel propagation to the local magnetic field. Amplitude and phase correlation data analysis allowed us to estimate the characteristic spatial correlation scale transverse to the local magnetic field to be in the 2800–3200 km range. Keywords. Electromagnetics (Random media and rough surfaces) – Magnetospheric physics (Plasma waves and in-stabilities) – Radio science (Remote sensing) (10.5194/angeo-28-1377-2010)
  DOI : 10.5194/angeo-28-1377-2010
• Formation of a sodium ring in Mercury's magnetosphere
  
  • Yagi Manabu
  • Seki K.
  • Matsumoto Y.
  • Delcourt Dominique C.
  • Leblanc François
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2010, 115 (A10), pp.A10253. We have performed a statistical analysis of exospheric sodium ion paths in Mercury's magnetosphere under northward interplanetary magnetic field conditions. Electric and magnetic field models used in the simulation were obtained from a global MHD simulation model, whereas the initial conditions of test Na+ ions were derived from a sodium exosphere model. We observe the formation of a ring-shaped high-pressure region consisting of energetic sodium ions traveling around the planet close to the equatorial plane. The configuration of this "sodium ring" as well as the acceleration processes leading to its formation strongly depend on the solar wind conditions. When the dynamic pressure is low, most of the Na+ are picked up in the magnetosphere and accelerated by the large-scale convective electric field. In contrast, in the case of high dynamic pressure, ions that are picked up in the magnetosheath and penetrate into the magnetosphere significantly contribute to the sodium ring. The configuration of this ring also depends upon the intensity of the solar wind electric field. Our analysis reveals that the pressure built by the Na+ ions may be significant as compared to the MHD pressure around the planet. (10.1029/2009JA015226)
  DOI : 10.1029/2009JA015226
• A comparison of global models for the solar wind interaction with Mars
  
  • Brain D.
  • Barabash S.
  • Boesswetter A.
  • Bougher S.
  • Brecht S.
  • Chanteur Gérard
  • Hurley D.
  • Dubinin Eduard
  • Fang X.
  • Fraenz M.
  • Halekas J.
  • Harnett E.
  • Holmstrom M.
  • Kallio E.
  • Lammer H.
  • Ledvina S.
  • Liemohn M.
  • Liu K.
  • Luhmann J.
  • Ma Y.
  • Modolo Ronan
  • Nagy A.
  • Motschmann U.
  • Nilsson Hans
  • Shinagawa H.
  • Simon Sunil
  • Terada N.
  Icarus, Elsevier, 2010, 206 (1), pp.139-151. We present initial results from the first community-wide effort to compare global plasma interaction model results for Mars. Seven modeling groups participated in this activity, using MHD, multi-fluid, and hybrid assumptions in their simulations. Moderate solar wind and solar EUV conditions were chosen, and the conditions were implemented in the models and run to steady state. Model output was compared in three ways to determine how pressure was partitioned and conserved in each model, the location and asymmetry of plasma boundaries and pathways for planetary ion escape, and the total escape flux of planetary oxygen ions. The two participating MHD models provided similar results, while the five sets of multi-fluid and hybrid results were different in many ways. All hybrid results, however, showed two main channels for oxygen ion escape (a pickup ion 'plume' in the hemisphere toward which the solar wind convection electric field is directed, and a channel in the opposite hemisphere of the central magnetotail), while the MHD models showed one (a roughly symmetric channel in the central magnetotail). Most models showed a transition from an upstream region dominated by plasma dynamic pressure to a magnetosheath region dominated by thermal pressure to a low altitude region dominated by magnetic pressure. However, calculated escape rates for a single ion species varied by roughly an order of magnitude for similar input conditions, suggesting that the uncertainties in both the current and integrated escape over martian history as determined by models are large. These uncertainties are in addition to those associated with the evolution of the Sun, the martian dynamo, and the early atmosphere, highlighting the challenges we face in constructing Mars' past using models. (10.1016/j.icarus.2009.06.030)
  DOI : 10.1016/j.icarus.2009.06.030
• Three-dimensional structure of electron density fluctuations in the Hall thruster plasma: ExB mode
  
  • Tsikata Sedina
  • Honoré Cyrille
  • Lemoine N.
  • Grésillon D.
  Physics of Plasmas, American Institute of Physics, 2010, 17, pp.112110. Collective scattering measurements have been conducted on the plasma of a Hall thruster, in which the electron density fluctuations are fully characterized by the dynamic form factor. The dynamic form factor amplitude distribution has been measured depending on the k-vector spatial and frequency components at different locations. Fluctuations are seen as propagating waves. The largest amplitude mode propagates nearly along the cross-field direction but at a phase velocity that is much smaller than the E×B drift velocity. Refined directional analysis of this largest amplitude mode shows a thin angular emission diagram with a mean direction that is not strictly along the E×B direction but at small angles near it. The deviation is oriented toward the anode in the (E,E×B) plane and toward the exterior of the thruster channel in the (B,E×B) plane. The density fluctuation rate is on the order of 1%. These experimentally determined directional fluctuation characteristics are discussed with regard to the linear kinetic theory model and particle-in-cell simulation results. (10.1063/1.3499350)
  DOI : 10.1063/1.3499350
• Particle transport in low core turbulence Tore-Supra plasmas
  
  • Guirlet R.
  • Sirinelli A.
  • Parisot T.
  • Sabot R.
  • Artaud J.F.
  • Bourdelle C.
  • Garbet X.
  • Hennequin Pascale
  • Hoang G.T.
  • Imbeaux Frédéric
  • Segui J.-L.
  • Mazon D.
  • Villegas D.
  Nuclear Fusion, IOP Publishing, 2010, 50, pp.095009. Electron and impurity transport has been studied in sawtoothing plasmas in the Tore-Supra tokamak. High time and space resolution measurements of the electron density reveal the existence of a flat profile region encompassing the q = 1 surface, on which is superimposed a density peak building up between sawtooth relaxations. For the first time in this regime, we have determined the underlying transport of both nickel and electrons independently of the effect of sawteeth in the central part of the plasma. Electron transport is consistent with the neoclassical expectations only in the close vicinity of the magnetic axis. Further out, it exceeds the neoclassical values as calculated with the NCLASS code, although the turbulence level is very low in the whole central region region. In contrast, nickel transport is in good agreement with the neoclassical calculations in the same region. The neoclassical effect on trapped particles of a persisting mode due to incomplete reconnection of the magnetic surfaces is consistent with these observations. (10.1088/0029-5515/50/9/095009)
  DOI : 10.1088/0029-5515/50/9/095009
• Design criteria and validation of a vacuum load current multiplier on a mega-ampere microsecond inductive storage generator
  
  • Chuvatin Alexandre S.
  • Kim A. A.
  • Kokshenev V. A.
  • Kovalchuk Boris M.
  • Lassalle Francis
  • Calamy Hervé
  • Krishnan M.
  Laser and Particle Beams, Cambridge University Press (CUP), 2010, 28 (3), pp.361-369. The load current multiplier concept (LCM) was suggested for improving the energy transfer efficiency from pulse power generators to loads. The concept was initially demonstrated at atmospheric pressure and dielectric insulation on a compact, 100 kA, microsecond capacitor bank. This paper reports on the LCM design criteria for mega-ampere vacuum pulse power when the LCM comprises a large-inductance magnetic flux extruder cavity without a magnetic core. The analytical and numerical design approach presented was experimentally validated on GIT12 mega-ampere inductive energy storage generator with a constant-inductance load. The LCM technique increased the peak load current from typically 4.6 MA at 1.87 µs on this generator, to 6.43 MA at 2.0 µs. The electromagnetic power into a ~10 nH load increased from 100 GW to 230 GW. This result is in good agreement with the presented numerical simulations and it corresponds to a 95% increase of the achievable magnetic pressure at 8 cm radius in the load. The compact, LCM hardware allows the GIT12 generator to operate more efficiently without modifying the stored energy or architecture. The demonstrated load power and energy increase using the LCM concept is of importance for further studies on power amplification in vacuum and high energy density physics. (10.1017/S0263034610000224)
  DOI : 10.1017/S0263034610000224
• Whistler waves guided by density depletion ducts in a magnetoplasma
  
  • Bakharev P. V.
  • Zaboronkova T. M.
  • Kudrin A. V.
  • Krafft C.
  Fizika Plazmy / Plasma Physics Reports, MAIK Nauka/Interperiodica, 2010, 36 (11), pp.919-930. The guided propagation of whistler waves along cylindrical density depletion ducts in a magneto-plasma is studied. It is shown that, under certain conditions, such ducts can support volume and surface eigenmodes. The dispersion properties and field structure of whistler modes guided by density depletion ducts are analyzed. The effect of collisional losses in the plasma on the properties of modes is discussed. (10.1134/S1063780X10110012)
  DOI : 10.1134/S1063780X10110012
• Théorie des Plasmas
  
  • Firpo Marie-Christine
  Flash X - La revue scientifique de l'Ecole polytechnique, Ecole polytechnique, 2010, 12, pp.26-27. ISSN : 1775-0385
• Design of magnetic concentrators for high sensitivity anisotropic magnetoresistor devices
  
  • Mansour Malik
  • Coillot Christophe
  • Chanteur Gérard
  • Roux A.
  • Nguyen van Dau Frédéric
  Journal of Applied Physics, American Institute of Physics, 2010, 107, pp.09E707. In this work, a very promising shape of magnetic concentrators taking advantage of the symmetrical flux leakage of Mn-Zn ferrite magnetic cores is presented. This configuration consists of two ferromagnetic rods separated by two air gaps allowing to place anisotropic magnetoresistance sensors in the core axis. Results from three-dimensional finite elements modeling are presented. We show that an appropriate shape optimization of core extremities enables to improve significantly the amplification factor without any increase in length. (10.1063/1.3337747)
  DOI : 10.1063/1.3337747