Publications

2009

• Turbulence in the TORE SUPRA Tokamak: Measurements and Validation of Nonlinear Simulations
  
  • Casati A.
  • Gerbaud T.
  • Hennequin P.
  • Heuraux Stéphane
  Physical Review Letters, American Physical Society, 2009, 102, pp.165005. Turbulence measurements in TORE SUPRA tokamak plasmas have been quantitatively compared to predictions by nonlinear gyrokinetic simulations. For the first time, numerical results simultaneously match within experimental uncertainty (a) the magnitude of effective heat diffusivity, (b) rms values of density fluctuations, and (c) wave-number spectra in both the directions perpendicular to the magnetic field. Moreover, the nonlinear simulations help to revise as an instrumental effect the apparent experimental evidence of strong turbulence anisotropy at spatial scales of the order of ion-sound Larmor radius.
• FLUCTUATION MEASUREMENTS AND THEIR LINK WITH TRANSPORT ON TORE SUPRA
  
  • Sabot R.
  • Hennequin Pascale
  • Colas L.
  Fusion Science and Technology, Taylor & Francis, 2009, 56 (3), pp.1253-1272. Measurement of turbulence properties provides key insight to understand anomalous transport in magnetic fusion devices. On Tore Supra, scattering diagnostics and reflectometers have been used to measure density fluctuations in the plasma core. A cross-polarization scattering diagnostic was also the first diagnostic to measure the turbulence magnetic fluctuations in a fusion plasma core. This paper presents the principle and the experimental setup of these diagnostics, with chosen results illustrating their capabilities to determine the spatial structure of the turbulence and to assess the link between energy transport and fluctuations. These flexible and complementary measurements made it possible to analyze the confinement and fluctuation scaling laws with non-dimensional parameters, which requires a wide variety of plasma conditions.
• A review of new wire arrays with open and closed magnetic configurations at the 1.6 MA Zebra generator for radiative properties and opacity effects
  
  • Kantsyrev Viktor L.
  • Safronova Alla S.
  • Esaulov A. A.
  • Williamson Kenneth M.
  • Shrestha Ishor
  • Yilmaz M. F.
  • Osborne Glenn C.
  • Weller Michael E.
  • Ouart N. D.
  • Shlyaptseva V. V.
  • Rudakov Leonid I.
  • Chuvatin Alexandre S.
  • Velikovich A. L.
  High Energy Density Physics, Elsevier, 2009, 5 (3), pp.115-123. Review The studies emphasize investigation of plasma formation, implosion, and radiation features as a function of two load configurations: compact multi-planar and cylindrical wire arrays. Experiments with different Z-pinch loads were performed on 1.6 MA, 100 ns, Zebra generator at University of Nevada, Reno. The multi-planar wire arrays (PWAs) were studied in open and closed configurations with Al, Cu, brass, Mo and W wires. In the open magnetic configurations (single, double, triple PWAs) magnetic fields are present inside the arrays from the beginning of discharge, while in closed configurations (prism-like PWA) the global magnetic field is excluded inside before plasma flow occurs. The new prism-like PWA allows high flexibility in control of implosion dynamics and precursor formation. The spectral modeling, magneto-hydrodynamic (MHD) and wire ablation dynamic model (WADM) codes were used to describe the plasma evolution and plasma parameters. Experimentally observed electron temperature and density in multiple bright spots reached 1.4 keV and 5 × 10E21 cm−3, respectively. Two types of bright spots were observed. With peak currents up to 1.3 MA opacity effects became more pronounced and led to a limiting of the X-ray yields from compact cylindrical arrays. Despite different magnetic energy to plasma coupling mechanisms early in the implosion a comparison of compact double PWA and cylindrical WA results indicates that during the stagnation stage the same plasma heating mechanism may occur. The double PWA was found to be the best radiator tested at University scale 1 MA generator. It is characterized by a combination of larger yield and power, mm-scale size, and provides the possibility of radiation pulse shaping. Further, the newer configuration, the double PWA with skewed wires, was tested and showed the possibility of a more effective X-ray generation. (10.1016/j.hedp.2009.04.001)
  DOI : 10.1016/j.hedp.2009.04.001
• Kelvin-Helmholtz waves at the Earth's magnetopause: Multiscale development and associated reconnection
  
  • Hasegawa H.
  • Retinò Alessandro
  • Vaivads A.
  • Khotyaintsev Y. V.
  • André M.
  • Nakamura T. K. M.
  • Teh W.-L.
  • Sonnerup B. U. Ö.
  • Schwartz S. J.
  • Seki Y.
  • Fujimoto M.
  • Saito Y.
  • Rème H.
  • Canu Patrick
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2009, 114, pp.12207. We examine traversals on 20 November 2001 of the equatorial magnetopause boundary layer simultaneously at 1500 magnetic local time (MLT) by the Geotail spacecraft and at 1900 MLT by the Cluster spacecraft, which detected rolled-up MHD-scale vortices generated by the Kelvin-Helmholtz instability (KHI) under prolonged northward interplanetary magnetic field conditions. Our purpose is to address the excitation process of the KHI, MHD-scale and ion-scale structures of the vortices, and the formation mechanism of the low-latitude boundary layer (LLBL). The observed KH wavelength (>4 × 10<SUP>4</SUP> km) is considerably longer than predicted by the linear theory from the thickness (1000 km) of the dayside velocity shear layer. Our analyses suggest that the KHI excitation is facilitated by combined effects of the formation of the LLBL presumably through high-latitude magnetopause reconnection and compressional magnetosheath fluctuations on the dayside, and that breakup and/or coalescence of the vortices are beginning around 1900 MLT. Current layers of thickness a few times ion inertia length 100 km and of magnetic shear 60° existed at the trailing edges of the vortices. Identified in one such current sheet were signatures of local reconnection: Alfvénic outflow jet within a bifurcated current sheet, nonzero magnetic field component normal to the sheet, and field-aligned beam of accelerated electrons. Because of its incipient nature, however, this reconnection process is unlikely to lead to the observed dusk-flank LLBL. It is thus inferred that the flank LLBL resulted from other mechanisms, namely, diffusion and/or remote reconnection unidentified by Cluster. (10.1029/2009JA014042)
  DOI : 10.1029/2009JA014042
• Time resolved quantum cascade laser absorption spectroscopy on NO containing pulsed DC discharges
  
  • Welzel S.
  • Guaitella Olivier
  • Pintassilgo C.D.
  • Rousseau Antoine
  • Roepcke J.
  , 2009.
• What can we learn from HF signal scattered from a discrete arc?
  
  • Seran Elena
  • Godefroy Michel
  • Kauristie K.
  • Cerisier Jean-Claude
  • Berthelier Jean-Jacques
  • Lester M.
  • Sarri L.-E.
  Annales Geophysicae, European Geosciences Union, 2009, 27 (5), pp.1887-1896. We present observations of a discrete southward propagating arc which appeared in the mid-night sector at latitudes equatorward of main substorm activity. The arc observations were made simultaneously by the ALFA (Auroral Light Fine Analysis) optical camera, the SuperDARN-CUTLASS HF radar and the Demeter satellite during a coordinated multi-instrumental campaign conducted at the KEOPS/ESRANGE site in December 2006. The SuperDARN HF signal which is often lost in the regions of strong electron precipitation yields in our case clear backscatter from an isolated arc of weak intensity. Consequently we are able to study arc dynamics, the formation of meso-scale irregularities of the electron density along the arc, compare the arc motion with the convection of surrounding plasma and discuss the contribution of ionospheric ions in the arc erosion and its propagation. (10.5194/angeo-27-1887-2009)
  DOI : 10.5194/angeo-27-1887-2009
• Capture of solar wind alpha-particles by the Martian atmosphere
  
  • Chanteur Gérard
  • Dubinin E.
  • Modolo Ronan
  • Fraenz M.
  Geophysical Research Letters, American Geophysical Union, 2009, 36 (23), pp.L23105. Integration along He++ test-particle trajectories in the self-consistent electromagnetic fields generated by three-dimensional hybrid simulations of the solar wind/Mars interaction is used to evaluate the removal of solar wind α-particles due to charge-exchange processes with neutral species of the Martian exosphere. The total removal rate of solar wind He++ ions, transformed into either singly ionised or neutral helium, is equal to 6.7 × 1023 s−1, which corresponds approximately to 30% of the flux of solar α-particles through the planetary cross-section. The deposition rate of helium neutral atoms, created by double electronic capture on exospheric oxygen, impacting the exobase, and penetrating below where it can be trapped, is about 1.5 × 1023 s−1. That means an important contribution of the solar wind source to the helium balance of the Martian atmosphere. The implantation of the solar helium into the Martian atmosphere shows an asymmetry related to the orientation of the motional electric field of the solar wind, −VSW × BIMF. (10.1029/2009GL040235)
  DOI : 10.1029/2009GL040235
• Dust Detection by the Wave Instrument on STEREO: Nanoparticles Picked up by the Solar Wind?
  
  • Meyer-Vernet N.
  • Maksimovic M.
  • Czechowski A.
  • Mann I. R.
  • Zouganelis I.
  • Goetz K.
  • Kaiser M. L.
  • St. Cyr O. C.
  • Bougeret J.-L.
  • Bale S. D.
  Solar Physics, Springer Verlag, 2009, 256 (1-2), pp.463-474. The STEREO wave instrument (S/WAVES) has detected a very large number of intense voltage pulses. We suggest that these events are produced by impact ionisation of nanoparticles striking the spacecraft at a velocity of the order of magnitude of the solar wind speed. Nanoparticles, which are half-way between micron-sized dust and atomic ions, have such a large charge-to-mass ratio that the electric field induced by the solar wind magnetic field accelerates them very efficiently. Since the voltage produced by dust impacts increases very fast with speed, such nanoparticles produce signals as high as do much larger grains of smaller speeds. The flux of 10-nm radius grains inferred in this way is compatible with the interplanetary dust flux model. The present results may represent the first detection of fast nanoparticles in interplanetary space near Earth orbit. (10.1007/s11207-009-9349-2)
  DOI : 10.1007/s11207-009-9349-2
• Regeneration of adsorbent/catalytic material by a Dielectric Barrier Discharge (DBD)
  
  • Youssef Joseph
  • Bouamra K.
  • Makarov M.
  • Guaitella Olivier
  • Rousseau Antoine
  , 2009.
• Influence of dielectric material on chemistry reactivity in Dielectric Barrier Discharge (DBD)
  
  • Youssef Joseph
  • Bouamra K.
  • Makarov M.
  • Guaitella Olivier
  • Rousseau Antoine
  , 2009.
• Long range correlation studies : Tore Supra contribution, DREVE project
  
  • Vermare Laure
  • Hennequin Pascale
  • Gürcan Özgür D.
  • Honoré Cyrille
  • Sabot R.
  • Giacalone J-C.
  • Tore Supra Team
  , 2009.
• Electrostatic solitary waves in current layers: from Cluster observations during a super-substorm to beam experiments at the LAPD
  
  • Pickett J. S.
  • Chen L.-J.
  • Santolík O.
  • Grimald S.
  • Lavraud B.
  • Verkhoglyadova O. P.
  • Tsurutani B. T.
  • Lefebvre B.
  • Fazakerley A.
  • Lakhina G. S.
  • Ghosh S. S.
  • Grison B.
  • Décréau Pierrette
  • Gurnett D. A.
  • Torbert R.
  • Cornilleau-Wehrlin Nicole
  • Dandouras I.
  • Lucek E.
  Nonlinear Processes in Geophysics, European Geosciences Union (EGU), 2009, 16 (3), pp.431-442. Electrostatic Solitary Waves (ESWs) have been observed by several spacecraft in the current layers of Earth's magnetosphere since 1982. ESWs are manifested as isolated pulses (one wave period) in the high time resolution waveform data obtained on these spacecraft. They are thus nonlinear structures generated out of nonlinear instabilities and processes. We report the first observations of ESWs associated with the onset of a super-substorm that occurred on 24 August 2005 while the Cluster spacecraft were located in the magnetotail at around 18-19 R<SUB>E</SUB> and moving northward from the plasma sheet to the lobes. These ESWs were detected in the waveform data of the WBD plasma wave receiver on three of the Cluster spacecraft. The majority of the ESWs were detected about 5 min after the super-substorm onset during which time 1) the PEACE electron instrument detected significant field-aligned electron fluxes from a few 100 eV to 3.5 keV, 2) the EDI instrument detected bursts of field-aligned electron currents, 3) the FGM instrument detected substantial magnetic fluctuations and the presence of Alfvén waves, 4) the STAFF experiment detected broadband electric and magnetic waves, ion cyclotron waves and whistler mode waves, and 5) CIS detected nearly comparable densities of H and O ions and a large tailward H velocity. We compare the characteristics of the ESWs observed during this event to those created in the laboratory at the University of California-Los Angeles Plasma Device (LAPD) with an electron beam. We find that the time durations of both space and LAPD ESWs are only slightly larger than the respective local electron plasma periods, indicating that electron, and not ion, dynamics are responsible for generation of the ESWs. We have discussed possible mechanisms for generating the ESWs in space, including the beam and kinetic Buneman type instabilities and the acoustic instabilities. Future studies will examine these mechanisms in more detail using the space measurements as inputs to models, and better relate the ESW space measurements to the laboratory through PIC code models. (10.5194/npg-16-431-2009)
  DOI : 10.5194/npg-16-431-2009
• Influence of dielectric material in Dielectric Barrier Discharge (DBD) for chemistry reactivity control
  
  • Youssef Joseph
  • Bouamra K.
  • Makarov M.
  • Guaitella Olivier
  • Rousseau Antoine
  , 2009.
• Oblique propagation of whistler mode waves in the chorus source region
  
  • Santolík O.
  • Gurnett D. A.
  • Pickett J. S.
  • Chum J.
  • Cornilleau-Wehrlin Nicole
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2009, 114. Whistler mode chorus has been shown to play a role in the process of local acceleration of electrons in the outer Van Allen radiation belt. Most of the quasi-linear and nonlinear theoretical studies assume that the waves propagate parallel to the terrestrial magnetic field. We show a case where this assumption is invalid. We use data from the Cluster spacecraft to characterize propagation and spectral properties of chorus. The recorded high-resolution waveforms show that chorus in the source region can be formed by a succession of discrete wave packets with decreasing frequency that sometimes change into shapeless hiss. These changes occur at the same time in the entire source region. Multicomponent measurements show that waves in both these regimes can be found at large angles to the terrestrial magnetic field. The hiss intervals contain waves propagating less than one tenth of a degree from the resonance cone. In the regime of discrete wave packets the peak of the wave energy density is found at a few degrees from the resonance cone in a broad interval of azimuth angles. The wave intensity increases with the distance from the magnetic field minimum along a given field line, indicating a gradual amplification of chorus in the source region. (10.1029/2009JA014586)
  DOI : 10.1029/2009JA014586
• Self synchronization of surface discharges in a two electrodes device
  
  • Allegraud Katia
  • Rousseau Antoine
  IEEE Transactions on Dielectrics and Electrical Insulation, Institute of Electrical and Electronics Engineers, 2009, 16 (2), pp.435-439. A twin electrode device coupled to the same high voltage power supply is used to study the propagation of surface streamers. These two identical electrodes are separated from the grounded one by a pyrex plate acting as a dielectric barrier. The gas is dry air, at atmospheric pressure. 1 ns time resolved imaging of the discharge propagation is performed to monitor the discharge ignition and propagation. The discharge consists in filaments which propagate on the dielectric as cathode directed streamers. Each filament transfers 1 nC. The propagation velocities vary from 3.4times107 cm/s at the beginning of the propagation to 7times106 cm/s at the end of the propagation. Ignition at one electrode triggers ignition at the other within 2 ns. (10.1109/TDEI.2009.4815175)
  DOI : 10.1109/TDEI.2009.4815175
• Time-dependent hydrodynamical simulations of slow solar wind, coronal inflows, and polar plumes
  
  • Pinto Rui
  • Grappin Roland
  • Wang Y-M
  • Léorat Jacques
  Astronomy & Astrophysics - A&A, EDP Sciences, 2009, 497 (2), pp.537--543. Aims. We explore the effects of varying the areal expansion rate and coronal heating function on the solar wind flow. Methods. We use a one-dimensional, time-dependent hydrodynamical code. The computational domain extends from near the photosphere, where nonreflecting boundary conditions are applied, to 30 , and includes a transition region where heat conduction and radiative losses dominate. Results. We confirm that the observed inverse relationship between asymptotic wind speed and expansion factor is obtained if the coronal heating rate is a function of the local magnetic field strength. We show that inflows can be generated by suddenly increasing the rate of flux-tube expansion and suggest that this process may be involved in the closing-down of flux at coronal hole boundaries. We also simulate the formation and decay of a polar plume, by including an additional, time-dependent heating source near the base of the flux tube. (10.1051/0004-6361/200811183)
  DOI : 10.1051/0004-6361/200811183
• Physics of non-diffusive turbulent transport of momentum and the origins of spontaneous rotation in tokamaks
  
  • Diamond P.H.
  • Mcdevitt C.J.
  • Gürcan Özgür D.
  • Hahm T.S.
  • Wang W.X.
  • Yoon E.S.
  • Holod I.
  • Lin Z.
  • Naulin V.
  • Singh R.
  Nuclear Fusion, IOP Publishing, 2009, 49, pp.045002. Recent results in the theory of turbulent momentum transport and the origins of intrinsic rotation are summarized. Special attention is focused on aspects of momentum transport critical to intrinsic rotation, namely the residual stress and the edge toroidal flow velocity pinch. Novel results include a systematic decomposition of the physical processes which drive intrinsic rotation, a calculation of the critical external torque necessary to hold the plasma stationary against the intrinsic residual stress, a simple model of net velocity scaling which recovers the salient features of the experimental trends and the elucidation of the impact of the particle flux on the net toroidal velocity pinch. Specific suggestions for future experiments are offered. (10.1088/0029-5515/49/4/045002)
  DOI : 10.1088/0029-5515/49/4/045002
• Wave-Number Spectrum of Drift-Wave Turbulence
  
  • Gürcan Özgür D.
  • Garbet X.
  • Hennequin Pascale
  • Diamond P.H.
  • Casati A.
  • Falchetto G. L.
  Physical Review Letters, American Physical Society, 2009, 102, pp.255002. A simple model for the evolution of turbulence fluctuation spectra, which includes neighboring interactions leading to the usual dual cascade as well as disparate scale interactions corresponding to refraction by large scale structures, is derived. The model recovers the usual Kraichnan-Kolmogorov picture in the case of exclusively local interactions and midrange drive. On the other hand, when disparate scale interactions are dominant, a simple spectrum for the density fluctuations of the form |nk|2&#8733;k&#8722;3/(1 k2)2 is obtained. This simple prediction is then compared to, and found to be in fair agreement with, Tore Supra CO2 laser scattering data. (10.1103/PhysRevLett.102.255002)
  DOI : 10.1103/PhysRevLett.102.255002
• Enhanced confinement with increased extent of the low magnetic shear region in tokamak plasmas
  
  • Nasi L.
  • Firpo Marie-Christine
  Plasma Physics and Controlled Fusion, IOP Publishing, 2009, 51, pp.045006. The Hamiltonian representation of magnetic field lines enables one to study their confinement properties in tokamaks through the use of symplectic maps such as the symmetric tokamap and its bounded version, the latter being introduced here. In this time-independent purely magnetic framework, we observed the drastic improvement in the confinement of magnetic field lines produced by the local vanishing of the shear profile. This amounts to a non-twist condition that notably acts in the same way the safety profile being (non-strictly) monotonic or having a reversed shear. We single out the effect of the amount of flatness of the safety profile in the vicinity of its zero shear point. All other things being equal, the beneficial effect of the vanishing of the shear profile is shown to be increased if the radial extent of the low-shear region is increased. To be specific, the low-shear region induces the formation of a belt of robust KAM tori acting as an internal transport barrier whose width is all the larger as the extent of the low-shear region is broad. (10.1088/0741-3335/51/4/045006)
  DOI : 10.1088/0741-3335/51/4/045006
• Global distribution of whistler-mode chorus waves observed on the THEMIS spacecraft
  
  • Li W.
  • Thorne R. M.
  • Angelopoulos V.
  • Bortnik J.
  • Cully C. M.
  • Ni B.
  • Le Contel Olivier
  • Roux A.
  • Auster U.
  • Magnes W.
  Geophysical Research Letters, American Geophysical Union, 2009, 36, pp.9104. Whistler mode chorus waves are receiving increased scientific attention due to their important roles in both acceleration and loss processes of radiation belt electrons. A new global survey of whistler-mode chorus waves is performed using magnetic field filter bank data from the THEMIS spacecraft with 5 probes in near-equatorial orbits. Our results confirm earlier analyses of the strong dependence of wave amplitudes on geomagnetic activity, confinement of nightside emissions to low magnetic latitudes, and extension of dayside emissions to high latitudes. An important new finding is the strong occurrence rate of chorus on the dayside at L > 7, where moderate dayside chorus is present >10% of the time and can persist even during periods of low geomagnetic activity. (10.1029/2009GL037595)
  DOI : 10.1029/2009GL037595
• Evidence of a Cascade and Dissipation of Solar-Wind Turbulence at the Electron Gyroscale
  
  • Sahraoui Fouad
  • Goldstein M. L.
  • Robert Patrick
  • Khotyaintsev Y. V.
  Physical Review Letters, American Physical Society, 2009, 102 (23), pp.231102. We report the first direct determination of the dissipation range of magnetofluid turbulence in the solar wind at the electron scales. Combining high resolution magnetic and electric field data of the Cluster spacecraft, we computed the spectrum of turbulence and found two distinct breakpoints in the magnetic spectrum at 0.4 and 35 Hz, which correspond, respectively, to the Doppler-shifted proton and electron gyroscales, f&#961;p and f&#961;e. Below f&#961;p, the spectrum follows a Kolmogorov scaling f&#8722;1.62, typical of spectra observed at 1 AU. Above f&#961;p, a second inertial range is formed with a scaling f&#8722;2.3 down to f&#961;e. Above f&#961;e, the spectrum has a steeper power law &#8764;f&#8722;4.1 down to the noise level of the instrument. We interpret this as the dissipation range and show a remarkable agreement with theoretical predictions of a quasi-two-dimensional cascade into Kinetic Alfvén Waves (KAW). (10.1103/PhysRevLett.102.231102)
  DOI : 10.1103/PhysRevLett.102.231102
• Whistler wave radiation from a loop antenna located in a cylindrical density depletion
  
  • Kudrin A. V.
  • Bakharev P. V.
  • Krafft C.
  • Zaboronkova T. M.
  Physics of Plasmas, American Institute of Physics, 2009, 16, pp.063502. Electromagnetic radiation from sources in a magnetoplasma containing a radially nonuniform cylindrical density depletion is considered. Using a rigorous solution for the total field comprising both the discrete and continuous parts of the spatial spectrum of excited waves, the radiation resistance of a loop antenna and the efficiency of excitation of different modes by such a source are determined in the whistler range. Based on the numerical results, conditions are revealed under which the power radiated from a loop antenna located in a density depletion is dominated by the contribution of either discrete- or continuous-spectrum modes. It is found that the radiation resistance of the loop antenna in a weakly nonuniform density depletion can be notably greater than that in a homogeneous magnetoplasma whose parameters coincide with those near the depletion axis. The results are relevant to the basic properties of whistler wave excitation in the presence of field-aligned plasma density irregularities and can be useful for wave diagnostics in laboratory and space plasmas. (10.1063/1.3142469)
  DOI : 10.1063/1.3142469
• Investigation of InP etching mechanisms in a Cl<SUB>2</SUB>/H<SUB>2</SUB> inductively coupled plasma by optical emission spectroscopy
  
  • Gatilova L.
  • Bouchoule S.
  • Guilet S.
  • Chabert Pascal
  Journal of Vacuum Science & Technology A, American Vacuum Society, 2009, 27, pp.262. Optical emission spectroscopy (OES) has been used in order to investigate the InP etching mechanisms in a Cl2H2 inductively coupled plasma. The authors have previously shown that anisotropic etching of InP could be achieved for a H2 percentage in the 35%45% range where the InP etch rate also presents a local maximum [ J. Vac. Sci. Technol. B 24, 2381 (2006) ], and that anisotropic etching was due to an enhanced passivation of the etched sidewalls by a silicon oxide layer [ J. Vac. Sci. Technol. B 26, 666 (2008) ]. In this work, it is shown that this etching behavior is related to a maximum in the H atom concentration in the plasma. The possible enhancement of the sidewall passivation process in the presence of H is investigated by comparing OES measurements and etching results obtained for Cl2H2 and Cl2Ar gas mixtures. (10.1116/1.3071950)
  DOI : 10.1116/1.3071950
• Auroral evidence for multiple reconnection in the magnetospheric tail plasma sheet
  
  • Treumann R. A.
  • Jaroschek C. H.
  • Pottelette Raymond
  EPL - Europhysics Letters, European Physical Society / EDP Sciences / Società Italiana di Fisica / IOP Publishing, 2009, 85, pp.49001. We present auroral evidence for multiple and, most probably, small-scale reconnection in the near-Earth magnetospheric plasma sheet current layer during auroral activity. Hall currents as the source of upward and downward field-aligned currents require the generation of the corresponding electron fluxes. The auroral spatial ordering in a multiple sequence of these fluxes requires the assumption of the existence of several ―-and possibly―- even many tailward reconnection sites. (10.1209/0295-5075/85/49001)
  DOI : 10.1209/0295-5075/85/49001
• Observations of Double Layers in Earth's Plasma Sheet
  
  • Ergun R. E.
  • Andersson L.
  • Tao J. B.
  • Angelopoulos V.
  • Bonnell J. W.
  • Mcfadden J. P.
  • Larson D. E.
  • Eriksson S.
  • Johansson T.
  • Cully C. M.
  • Newman D. N.
  • Goldman M. V.
  • Roux A.
  • Le Contel Olivier
  • Glassmeier K.-H.
  • Baumjohann W.
  Physical Review Letters, American Physical Society, 2009, 102, pp.155002. We report the first direct observations of parallel electric fields (E<SUB>||</SUB>) carried by double layers (DLs) in the plasma sheet of Earth's magnetosphere. The DL observations, made by the THEMIS spacecraft, have E<SUB>||</SUB> signals that are analogous to those reported in the auroral region. DLs are observed during bursty bulk flow events, in the current sheet, and in plasma sheet boundary layer, all during periods of strong magnetic fluctuations. These observations imply that DLs are a universal process and that strongly nonlinear and kinetic behavior is intrinsic to Earth's plasma sheet. (10.1103/PhysRevLett.102.155002)
  DOI : 10.1103/PhysRevLett.102.155002