Publications

2018

• The MSA Instrument (Mass Spectrum Analyzer) Onboard Bepi Colombo MMO (Mercury Magnetospheric Orbiter)
  
  • Delcourt Dominique
  • Saito Y.
  • Leblanc François
  • Verdeil Christophe
  • Yokota S.
  • Fraenz M.
  • Fischer H.
  • Fiethe B.
  • Katra Bruno
  • Fontaine Dominique
  • Illiano Jean-Marie
  • Berthelier Jean-Jacques
  • Belger A.
  • Bubenhagen F.
  • Krupp N.
  • Buhrke U.
  • Michalik H.
  • Krueger H.
  , 2018, pp.LPI Contrib. No. 2047. The launch of the Bepi Colombo spacecraft, MPO (Mercury Planetary Orbiter) and MMO (Mercury Magnetospheric Orbiter), will take place in the fall 2018 for an arrival and orbit insertion at Mercury at the end of 2025. The objective of the MMO spacecraft that is under responsibility of JAXA, is to thoroughly investigate the magnetized environment of Mercury. On this purpose, MMO payload includes in particular the MPPE (Mercury Plasma Particle Experiments) consortium that is an instrumental suite dedicated to particle measurements. MSA is one of these instruments that focuses on measurements of the Mercury Plasma Particle Experiment composition. Taking advantage of MMO spin (4s period), MSA will measure three-dimensional ion distributions over a large range of masses (1-60 amu) and energies (from 1 eV/q up to 38 keV/q). MSA consists of a spherical top-hat analyzer for energy selection, followed by a Time-Of- Flight chamber for mass identification. With its "reflectron" design, MSA offers a high mass resolution (typically, m/∆m > 50) that will allow for instance to distinguish between 39K and 40Ca ions. This capability will be of particular importance to identify the various species that populate Mercury’s magnetosphere and to characterize the interaction between the planet surface and the solar wind.
• Statistical Analysis of Solar Events Associated with Storm Sudden Commencements over One Year of Solar Maximum During Cycle 23: Propagation from the Sun to the Earth and Effects
  
  • Bocchialini K.
  • Grison B.
  • Menvielle Michel
  • Chambodut A.
  • Cornilleau-Wehrlin Nicole
  • Fontaine Dominique
  • Marchaudon Aurélie
  • Pick Monique
  • Pitout Frédéric
  • Schmieder Brigitte
  • Régnier S.
  • Zouganelis I.
  Solar Physics, Springer Verlag, 2018, 293 (5), pp.art. 75. Taking the 32 storm sudden commencements (SSCs) listed by the International Service of Geomagnetic Indices (ISGI) of the Observatory de l’Ebre during 2002 (solar activity maximum in Cycle 23) as a starting point, we performed a multi-criterion analysis based on observations (propagation time, velocity comparisons, sense of the magnetic field rotation, radio waves) to associate them with solar sources, identified their effects in the interplanetary medium, and looked at the response of the terrestrial ionized and neutral environment. We find that 28 SSCs can be related to 44 coronal mass ejections (CMEs), 15 with a unique CME and 13 with a series of multiple CMEs, among which 19 (68%) involved halo CMEs. Twelve of the 19 fastest CMEs with speeds greater than 1000 km s₋₁ are halo CMEs. For the 44 CMEs, including 21 halo CMEs, the corresponding X-ray flare classes are: 3 X-class, 19 M-class, and 22 C-class flares. The probability for an SSC to occur is 75% if the CME is a halo CME. Among the 500, or even more, front-side, non-halo CMEs recorded in 2002, only 23 could be the source of an SSC, i.e. 5%. The complex interactions between two (or more) CMEs and the modification of their trajectories have been examined using joint white-light and multiple-wavelength radio observations. The detection of long-lasting type IV bursts observed at metric–hectometric wavelengths is a very useful criterion for the CME–SSC events association. The events associated with the most depressed Dst values are also associated with type IV radio bursts. The four SSCs associated with a single shock at L1 correspond to four radio events exhibiting characteristics different from type IV radio bursts. The solar-wind structures at L1 after the 32 SSCs are 12 magnetic clouds (MCs), 6 interplanetary coronal mass ejections (ICMEs) without an MC structure, 4 miscellaneous structures, which cannot unambiguously be classified as ICMEs, 5 corotating or stream interaction regions (CIRs/SIRs), one CIR caused two SSCs, and 4 shock events; note than one CIR caused two SSCs. The 11 MCs listed in 3 or more MC catalogs covering the year 2002 are associated with SSCs. For the three most intense geomagnetic storms (based on Dst minima) related to MCs, we note two sudden increases of the Dst, at the arrival of the sheath and the arrival of the MC itself. In terms of geoeffectiveness, the relation between the CME speed and the magnetic-storm intensity, as characterized using the Dst magnetic index, is very complex, but generally CMEs with velocities at the Sun larger than 1000 km s₋₁ have larger probabilities to trigger moderate or intense storms. The most geoeffective events are MCs, since 92% of them trigger moderate or intense storms, followed by ICMEs (33%). At best, CIRs/SIRs only cause weak storms. We show that these geoeffective events (ICMEs or MCs) trigger an increased and combined auroral kilometric radiation (AKR) and non-thermal continuum (NTC) wave activity in the magnetosphere, an enhanced convection in the ionosphere, and a stronger response in the thermosphere. However, this trend does not appear clearly in the coupling functions, which exhibit relatively weak correlations between the solar-wind energy input and the amplitude of various geomagnetic indices, whereas the role of the southward component of the solar-wind magnetic field is confirmed. Some saturation appears for Dst values <−100 nT on the integrated values of the polar and auroral indices. (10.1007/s11207-018-1278-5)
  DOI : 10.1007/s11207-018-1278-5
• The MSA (Mass Spectrum Analyzer) onboard Bepi Colombo MMO (Mercury Magnetospheric Orbiter)
  
  • Delcourt Dominique
  • Saito Yoshifumi
  • Leblanc Frédéric
  • Verdeil Christophe
  • Yokota Shoichiro
  • Fraenz Markus
  • Fischer Henning
  • Fiethe Björn
  • Katra Bruno
  , 2018.
• Ion dynamics in the magnetospheric flanks of Mercury
  
  • Aizawa Sae
  • Delcourt Dominique
  • Terada Naoki
  , 2018.
• Sun Earth connections
  
  • Amory-Mazaudier Christine
  , 2018.
• Ion cyclotron emission (ICE) study on the ASDEX Upgrade tokamak
  
  • Ochoukov R.
  • Bobkov V.
  • Dunne M.
  • Faugel H.
  • García Muñoz M.
  • Geiger B.
  • Hennequin Pascale
  • Mcclement K.
  • Moseev D.
  • Nielsen S.
  • Rasmussen J.
  • Schneider P.
  • Weiland M.
  • Noterdaeme J.-M.
  • Asdex Upgrade Team The
  • Eurofusion Mst1 Team The
  , 2018.
• Compressible MHD and kinetic scale turbulence in the terrestrial magnetosheath: recent results from the Cluster and Themis spacecraft
  
  • Sahraoui Fouad
  , 2018.
• Experimental investigations on turbulence and transport in tokamak plasmas
  
  • Vermare Laure
  , 2018.
• Electron energization near the electron diffusion region of high beta asymmetric reconnection
  
  • Eriksson E.
  • Vaivads A.
  • Graham Daniel B.
  • Divin A. V.
  • Khotyaintsev Y. V.
  • Yordanova E.
  • André M.
  • Giles B. L.
  • Pollock C.
  • Russell C. T.
  • Le Contel Olivier
  • Torbert R.
  • Ergun R.
  • Lindqvist P. A.
  • Burch J. L.
  , 2018.
• Comparison between self-consistent 2D full-particle and test-particles simulations to investigate the origin of the Earths Ion Foreshock.
  
  • Savoini Philippe
  • Lembège Bertrand
  , 2018, 20, pp.EGU2018-13002. Backstreaming ion populations propagating along the interplanetary magnetic field are evidenced upstream of the Terrestrial curved bow shock and form the ion foreshock. Two distinct backstreaming populations have been identified by spacecrafts within the quasi-perpendicular shock region (i.e. for45o &#8804;&#952;Bn &#8804;90o, where &#952;Bn is the angle between the shock normal and the upstream magnetostatic field): so called (i) field-aligned ion beams (« FAB») characterized by a gyrotropic distribution, and (ii) gyro-phase bunched ions («GPB »), characterized by a NON gyrotropic distribution. The origin of these backstreaming ions can be analyzed within an « enlarged » upstream region near/around the front with the help of 2D PIC simulation of a curved shock, where full curvature effects, time of flight effects and both electrons and ions dynamics are fully included by a self consistent approach. ...
• Coherent structures and spectral energy transfer in turbulent plasma: a space-filter approach
  
  • Camporeale E.
  • Sorriso-Valvo L.
  • Califano F.
  • Retinò Alessandro
  , 2018, 20, pp.EGU2018-13008,. Plasma turbulence at scales of the order of the ion inertial length is mediated by several mechanisms, including linear wave damping, magnetic reconnection, formation and dissipation of thin current sheets, stochastic heating. It is now understood that the presence of localized coherent structures enhances the dissipation channels and the kinetic features of the plasma. However, no formal way of quantifying the relationship between scale-to-scale energy transfer and the presence of spatial structures has so far been presented. Here, we quantify such relationship analyzing the results of a two-dimensional high-resolution Hall-MHD simulation. In particular, we employ the technique of space-filtering to derive a spectral energy flux term which defines, in any point of the computational domain, the signed flux of spectral energy across a given wave number. The characterization of coherent structures is performed by means of a traditional two-dimensional wavelet transformation. By studying the correlation between the spectral energy flux and the wavelet amplitude, we demonstrate the strong relationship between scale-to-scale transfer and coherent structures. Furthermore, by conditioning one quantity with respect to the other, we are able for the first time to quantify the inhomogeneity of the turbulence cascade induced by topological structures in the magnetic field. Taking into account the low space-filling factor of coherent structures (i.e. they cover a small portion of space), it emerges that 80% of the spectral energy transfer (both in the direct and inverse cascade directions) is localized in about 50% of space, and 50% of the energy transfer is localized in only 25% of space.
• Determining the multi-spacecraft path across plasma structures from magnetic field data
  
  • Manuzzo Roberto
  • Rezeau Laurence
  • Denton R. E.
  • Belmont Gérard
  • Califano F.
  , 2018.
• Magnetospheric MultiScale observations of energetic ion acceleration at multiple turbulent jet fronts
  
  • Retinò Alessandro
  , 2018, 20, pp.16310. Plasma jets in astrophysical plasma frequently lead to the formation of kinetic-scale boundaries, often referred to as jet fronts, which separate the hot jetting from the colder ambient plasma ahead of the jet. In the Earth's magnetotail, jets fronts are often associated with reconnection and are observed by spacecraft as a steep increase in the component of the magnetic field normal to the current sheet, accompanied by a plasma temperature increase and density decrease. Jet fronts play an important role in ion acceleration in the magnetotail. However, how exactly the different ion species get accelerated is still unclear. Recent high-resolution measurements of ion distribution functions in the magnetotail from the Magnetospheric MultiScale (MMS) spaceraft allow now for the first time to study the acceleration mechanisms in detail and their dependence on the ion species. Here present an event with multiple turbulent jet fronts observed by MMS in the magnetotail. Such fronts have also been recently reproduced by Particle-In-Cell numerical simulations. We investigate the acceleration of protons and heavier ions due to the interaction of fronts and the role of jets' turbulence for the energization.
• Plasma acceleration on multiscale temporal variations of electric and magnetic fields during substorm dipolarization in the Earths magnetotail
  
  • Parkhomenko E.
  • Malova H. V.
  • Grigorenko E. E.
  • Popov V. Y.
  • Petrukovich A. A.
  • Delcourt Dominique
  • Kronberg E. A.
  • Daly P.
  • Zelenyi L. M.
  , 2018, 20, pp.EGU2018-16323-1. Magnetic field dipolarizations are often observed in the magnetotail during substorms. These generally include three temporal scales: (1) actual dipolarization when the normal magnetic field changes during several minutes from minimum to maximum level ; (2) sharp bursts (pulses) interpreted as the passage of multiple dipolarization fronts with characteristic time scales < 1 min, and (3) bursts of electric and magnetic fluctuations with frequencies up to electron gyrofrequency occurring at the smallest time scales (&#8804; 1 s). We present a numerical model where the contributions of the above processes (1)-(3) in particle acceleration are analyzed. It is shown that these pro- cesses have a resonant character at different temporal scales. While O ions are more likely accelerated due to the mechanism (1), H ions (and to some extent electrons) are effectively accelerated due to the second mechanism. High-frequency electric and magnetic fluctuations accompanying magnetic dipolarization as in (3) are also found to efficiently accelerate electrons.
• Magnetospheric MultiScale observations of ion acceleration at jet fronts
  
  • Catapano F.
  • Mms Team
  , 2018, 20, pp.EGU2018-14005-1. Plasma jet fronts in the Earths magnetotail are kinetic-scale boundaries separating hot fast plasma jets, generally attributed to reconnection outflows, from colder ambient plasma. Jet fronts are typically associated with a sharp increase of the vertical component of the magnetic field Bz, an increase of the plasma temperature and a drop of plasma density. Spacecraft observations and numerical simulations indicate that jet fronts are sites of major ion acceleration. Yet the exact acceleration mechanisms as well as the dependence of such mechanisms on ion composition are not fully understood. Recent Magnetospheric MultiScale (MMS) spacecraft high-resolution measurements of ion distribution functions in the magnetotail allow for the first time to study the acceleration mechanisms in detail. Here, we show an example of two jet fronts propagating earthward with different velocities. The faster jet is following the slower jet and observations of electric and magnetic fields in the region between the two jets are consistent with the formation of a magnetic island, in agreement with Particle-In- Cell numerical simulations. Observations are consistent with ions trapped in the island and accelerated in a magnetic bottle. We also discuss the acceleration mechanisms of different ion species (H , He , O ) ahead of the first, slower jet and we discuss how such mechanisms depend on the ion species.
• Machine learning methods to identify ICMEs automatically
  
  • Nguyen Gautier
  • Fontaine Dominique
  • Aunai N.
  • Vandenbossche J.
  • Jeandet A.
  • Lemaitre G.
  • Kegel B.
  • Le Pennec E.
  , 2018, 20, pp.EGU2018-1963. Magnetic instabilities in the solar corona lead to the expulsion of large quantities of plasma and magnetic field in the interplanetary medium known as Interplanetary Coronal Mass Ejections (ICMEs). Among them, magnetic clouds (MCs) are characterized by a low proton temperature and plasma parameter &#946;, an enhanced magnetic field intensity with a smooth rotation of its vector components (i.e the presence of a flux rope), and a low level of fluc- tuations. As the solar wind is usually supersonic and super alfvenic, MCs can eventually follow a turbulent sheath characterized by a large magnetic field intensity, high &#946; and temperature, an enhanced proton density, the possible presence of an upstream MHD shock and a high level of magnetic fluctuations. As shown by Shinde and Russell (2003), manual identification of ICME is often subject to biases, which leads to disagreement between the existing ICMEs lists.To overcome it, Lepping et al. (2005) proposed an automatic identification method based on thresholds on the different MCs characteristics. The method demonstrated a good recall but a large percentage of false positives in the detected MCs. From the in situ measurements provided by the spacecraft Wind over the period 1997-2015 along with their manual annotation, we provide an automatic identification method for any new measurements using different machine learning algorithms., The adaptability of these algorithms combined to the results they provide indicates a possibility to apply them to detection of other events measured in situ by spacecrafts.
• Observations of the Electron Jet Generated by Secondary Reconnection in the Magnetotail
  
  • Huang S. Y.
  • Jiang K.
  • Yuan Z.
  • Sahraoui Fouad
  • He L.
  • Zhou M.
  • Fu H.
  • Deng X.
  • He J.
  • Cao D.
  • Yu X.
  • Wang D.
  , 2018, 20, pp.EGU2018-2647. We report in-situ observations of an electron jet generated by secondary reconnection within the outflow region of primary reconnection in the magnetotail by the Magnetospheric Multiscale (MMS) mission. MMS spacecraft firstly passed through the primary X-line, and then crossed the electron jet in the outflow of primary reconnection. There are a series of small-scale flux ropes in the secondary reconnection region. Decoupling from the magnetic field for both ions and electrons, intense out-of-plane current, and unambiguous Hall currents and Hall electromagnetic field appear in the electron jet. Strong electron dissipation (J*E > 0), nonzero electric field in the electron frame (E =E Ve×B6=0) and electron crescent-like shaped distributions are detected in the center of electron jet, implying that MMS spacecraft were likely passing through the electron diffusion region. The significant electron dissipation in the electron jet indicates that electron jet may be another electron acceleration channel in the reconnection region besides electron diffusion region.
• Optimal Field Gradients Derived from Multi-Spacecraft Observations
  
  • Chanteur Gérard
  , 2018, 20, pp.EGU2018-4437. The MMS mission offers the unique opportunity to check the quality of magnetic gradient estimates made by multi-spacecraft analysis methods. Particle detectors onboard MMS have enough energy and time resolution to provide ion and electron currents hence the electric particle current Jp. Magnetic records from the four spacecraft are used to estimate the tensor gradient of the vector magnetic field from which the magnetometer current Jm and divB are derived. Since the early 90s when preparing the CLUSTER mission several methods have been designed for estimating gradients of vector fields which differ by their approaches and abilities meanwhile they all give the same weight to the four spacecraft. The theory based on reciprocal vectors allows a detailed analysis of errors affecting the estimated components of the tensor gradient of a vector field which demonstrates that less regular is the tetrahedron larger are the uncertainties. An alternative to this Standard Reciprocal Vectors (SRVs) approach is the Generalized Reciprocal Vectors (GRVs) approach which improves the estimate of the gradient when the tetrahedron is not regular. GRVs will be introduced first, and then shown to improve the estimated divergence of B and the agreement between Jp and Jm on two MMS event cases. GRVs applied to CLUSTER data lead to an improved estimation of divB, i.e. closer to zero, meanwhile leading to new current estimates. It is expected that improving divB with CLUSTER data is an indication of improvement of the estimated current as for MMS data. It should nevertheless be mentioned that deformations of the tetrahedron are much smaller for MMS than for CLUSTER.
• Anomalous effects on magnetopause reconnection: The role of lower hybrid waves
  
  • Graham Daniel B.
  • Khotyaintsev Y. V.
  • Vaivads A.
  • André M.
  • Norgren C.
  • Drake J. F.
  • Lindqvist P. A.
  • Le Contel Olivier
  • Ergun R.
  • Gershman D. J.
  • Giles B. L.
  • Russell C. T.
  • Magnes W.
  • Burch J. L.
  • Torbert R.
  • Hwang K.-J.
  • Dokgo K.
  , 2018.
• Analysis of a fast flow series associated with a substorm event detected by MMS
  
  • Le Contel Olivier
  • Breuillard Hugo
  • Retinò Alessandro
  • Catapano F.
  • Alexandrova Alexandra
  • Nakamura R.
  • Chust Thomas
  • Mirioni Laurent
  • Turner D. L.
  • Cohen I.
  • Leonard T.
  • Jacquey C.
  • Lavraud B.
  • Gershman D. J.
  • Fuselier S. A.
  • Argall M.
  • Fischer D.
  • Graham Daniel B.
  • Huang S. Y.
  • Mms Team
  , 2018, 20, pp.EGU2018-16724. In July 2017, the MMS constellation was evolving in the magnetotail with an apogee of 25 Earth radii and an average inter-satellite distance of 10 km (i.e. at electron scales). On 23rd of July around 16:19 UT, MMS was located at the edge of the current sheet which was in a quasi-static state. Then, MMS suddenly entered in the central plasma sheet and detected the local onset of a small substorm as indicated by the AE index (&#8764;400 nT). Fast earthward plasma flows were measured during about 1 hour starting with a period of quasi-steady flow and followed by a saw-tooth like series of plasma jets. This plasma transport sequence ended up by a flow reversal still occurring close to the magnetic equator. Thanks to the unprecedented MMS measurement capability, these different phases are analyzed in terms of wave activity, current signatures, particle acceleration and heating. The origin of these two phases of plasma transport is discussed.
• Automatic detection of martian plasma boundaries: use of machine learning techniques
  
  • Ecoffet D.
  • Génot V.
  • Garnier P.
  • Aunai N.
  , 2018, 20, pp.EGU2018-3258. The planetary environments have been or are being visited by different space probes whose measurements make it possible to understand the dynamics of these environments and their evolution. Researchers spend much time to go through the spacecraft instruments time series to detect "events" or "boundaries" that are characterized by variations of one or more parameters. Depending on their nature, empirical or theoretical models can help predicting their occurrence more or less precisely, but still the identification "by eye" almost always remains the most efficient way. In this paper we report a tentative use of machine learning techniques, widely used in other fields (e.g. image recognition, sound analysis...), to automatically detect plasma boundaries at Mars (such as the shock, the photoelectron boundary or the magnetic pile-up boundary). Such an identification will ease statistical studies of the boundaries dynamics or provide added value to the users of planetary data visualisation systems (such as the CDPP - Plasma Physics Data Center) with a direct labeling of the plasma data in terms of boundaries/regions.
• Ray tracing study of propagation of lower-band whistler-mode emissions in outer radiation belts: A statistical approach
  
  • Hanzelka M.
  • Santolík O.
  • Cornilleau-Wehrlin Nicole
  , 2018, 20, pp.EGU2018-4386. Lower-band whistler-mode electromagnetic waves play an important role in the dynamics of outer radiation belts. To improve our understanding of ocurrence and behavior of these emissions, we run series of ray tracing simula- tions in non-relativistic hot plasma for a broad range of initial conditions, analyse the spatial dependence of wave properties and compare our results with long-term experimental data from the Cluster mission. The focus of the study is on the wave vector angle and wave intensity distribution of chorus emissions at higher latitudes. In this region, realistic empirical models of electron density distribution and Earths magnetic field are employed to obtain reliable data from the simulation. Damping and growth of waves is computed during the propagation, based on an empirical model of electron flux in outer magnetosphere. Other wave properties of importance are ellipticity of polarization and Poynting vector angle, analysed here in dependence on latitude and magnetic field line.
• Magnetospheric MultiScale observations of energetic ion acceleration at multiple turbulent jet fronts
  
  • Retinò Alessandro
  • Mms Team
  , 2018, 20, pp.EGU2018-16310-1. Geophysical Research Abstracts Plasma jets in astrophysical plasma frequently lead to the formation of kinetic-scale boundaries, often referred to as jet fronts, which separate the hot jetting from the colder ambient plasma ahead of the jet. In the Earths magnetotail, jets fronts are often associated with reconnection and are observed by spacecraft as a steep increase in the component of the magnetic field normal to the current sheet, accompanied by a plasma temperature increase and density decrease. Jet fronts play an important role in ion acceleration in the magnetotail. However, how exactly the different ion species get accelerated is still unclear. Recent high-resolution measurements of ion distribution functions in the magnetotail from the Magnetospheric MultiScale (MMS) spaceraft allow now for the first time to study the acceleration mechanisms in detail and their dependence on the ion species. Here present an event with multiple turbulent jet fronts observed by MMS in the magnetotail. Such fronts have also been recently reproduced by Particle-In-Cell numerical simulations. We investigate the acceleration of protons and heavier ions due to the interaction of fronts and the role of jets turbulence for the energization.
• On the current reduction by cold ions in magnetic reconnection: PIC simulations and MMS observations
  
  • Toledo-Redondo Sergio
  • Dargent Jérémy
  • Aunai Nicolas
  • Lavraud B.
  • André M.
  • Li W.
  • Giles B. L.
  • Lindqvist P.-A.
  • Ergun R.
  • Russell C. T.
  • Burch J. L.
  , 2018.
• Mid-altitude cusp properties: simultaneous Cluster observations at different MLT sectors
  
  • Bogdanova Y.
  • Fazakerley A.
  • Escoubet P.
  • Fear R.
  • Pitout F.
  • Trattner K. J.
  • Berchem J.
  • André M.
  • Canu Patrick
  • Carr C. M.
  • Dandouras I.
  • Khotyaintsev Y. V.
  • Kistler L. M.
  • Mouikis C.
  • Rauch Jean-Louis
  , 2018.