Publications

2018

• Observations of electron vortex magnetic holes and related wave-particle interactions in the turbulent magnetosheath
  
  • Huang S. Y.
  • Sahraoui Fouad
  • Yuan Z.
  • He J.
  • Zhao J.
  • Du J.
  • Le Contel Olivier
  • Deng X.
  • Zhou M.
  • Fu H.
  • Breuillard Hugo
  • Yu X.
  • Wang D.
  • Mms Team
  , 2018, 20, pp.EGU2018-11015. Magnetic hole is characterized by a magnetic depression, a density peak, a total electron temperature increase (with a parallel temperature decrease but a perpendicular temperature increase), and strong currents carried by the electrons. The current has a dip in the core region of the magnetic hole and a peak in the outer region of the magnetic hole. There is an enhancement in the perpendicular electron fluxes at 90&#9702; pitch angles inside the magnetic hole, implying that the electrons are trapped within it. The variations of the electron velocity components Vem and Ven suggest that an electron vortex is formed by trapping electrons inside the magnetic hole in the circular cross-section. These observations demonstrate the existence of a new type of coherent structures behaving as an electron vortex magnetic hole in turbulent space plasmas as predicted by recent kinetic simulations. We perform a statistically study using high time solution data from the MMS mission. The magnetic holes with short duration (i.e. < 0.5 s) have their cross section smaller than the ion gyro-radius. Superposed epoch analysis of all events reveals that an increase in the electron density and total temperature, significantly increase (resp. decrease) the electron perpendicular (resp. parallel) temperature, and an electron vortex inside the holes. Electron fluxes at &#8764;90&#9702; pitch angles with selective energies increase in the KSMHs, are trapped inside KSMHs and form the electron vortex due to their collective motion. All these features are consistent with the electron vortex magnetic holes obtained in 2D and 3D particle-in-cell simulations, indicating that the observed the magnetic holes seem to be best explained as electron vortex magnetic holes. It is furthermore shown that the magnetic holes are likely to heat and accelerate the electrons. We also investigate the coupling between whistler waves and electron vortex magnetic holes. These whistler waves can be locally generated inside electron vortex magnetic holes by electron temperature anisotropic instability.
• Impact of the Eulerian chaos of magnetic field lines in magnetic reconnection
  
  • Firpo Marie-Christine
  • Ettoumi Wahb
  • Lifschitz A.F.
  • Retinò Alessandro
  • Farengo R.
  • Ferrari H.E.
  • García-Martínez P.L.
  , 2018.
• Analysis of a fast flow series associated with a substorm event detected by MMS
  
  • Le Contel Olivier
  • Breuillard Hugo
  • Retinò Alessandro
  • Catapano Filomena
  • Alexandrova Alexandra
  • Nakamura Rumi
  • Chust Thomas
  • Mirioni Laurent
  • Turner Drew
  • Cohen Ian
  • Leonard Trevor
  • Jacquey Christian
  • Lavraud Benoit
  • Gershman Daniel J.
  • Fuselier Stefen A.
  • Argall Matthew R.
  • Fischer David
  • Graham Daniel
  • Huang Shiyong
  , 2018, pp.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 ( 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.
• Compressible MHD turbulence in the Earths magnetosheath: estimation of the energy cascade rate using in-situ spacecraft data
  
  • Hadid Lina
  • Sahraoui Fouad
  • Galtier Sébastien
  • Huang S. Y.
  , 2018.
• Hybrid simulations of plasma turbulence in support of space missions: a direct quantitative comparison with MMS observations
  
  • Franci L.
  • Stawarz J. E.
  • Landi S.
  • Hellinger P.
  • Chen C. H. K.
  • Burgess D.
  • Papini E.
  • Matteini L.
  • Verdini Andrea
  • Burch J. L.
  • Giles B. L.
  • Le Contel Olivier
  • Lindqvist P.-A.
  • Torbert R.
  • Ergun R. E.
  • Russell C. T.
  , 2018.
• The Alfvén Mission for the ESA M5 Call
  
  • Fazakerley A.
  • Berthomier Matthieu
  , 2018.
• Power spectra in the sheath of shock-driven ICMEs
  
  • Moissard C.
  , 2018, pp.1883.
• Network approach to turbulence, waves and flows
  
  • Gürcan Özgür D.
  , 2018.
• Plasma acceleration on multiscale temporal variations of electric and magnetic fields during substorm dipolarization in the Earth’s magnetotail
  
  • Parkhomenko Elena
  • Malova Helmi
  • Grigorenko Elena
  • Alekseevich-Petrukovich Anatolii
  • Delcourt Dominique
  • Aleksandrovna-Kronberg Elena
  • Daly Peter A.
  • Matveevich-Zelenyi Lev
  , 2018.
• Shell models applied to kinetic turbulence of trapped particles in magnetized plasmas
  
  • Xu Shaokang
  • Morel Pierre
  • Gürcan Özgür D.
  , 2018.
• Nonlinear wave-particle dynamics of energetic-particle driven instabilities in tokamak plasmas
  
  • Biancalani A.
  • Chavdarovski I.
  • Qiu Z.
  • Bottino A.
  • del Sarto D.
  • Ghizzo A.
  • Gürcan Özgür D.
  • Morel Pierre
  • Novikau I.
  , 2018.
• Narrow-Linewidth Picosecond Optical Parametric Oscillator for Backscatter Absorption Gas Imaging
  
  • Walter Guillaume
  • Dherbecourt Jean-Baptiste
  • Melkonian Jean-Michel
  • Raybaut Myriam
  • Henry Didier
  • Drag Cyril
  • Godard Antoine
  , 2018. A picosecond OPO combining an aperiodically-poled nonlinear crystal and a chirped VBG is used for backscatter absorption gas imaging of N2O at atmospheric pressure. The tunability is 215 nm around 3.82 μm in 130 ms.
• Training on GNSS and Space Weather in Africa in the framework of a North-South scientific network GIRCEA
  
  • Amory-Mazaudier Christine
  • Fleury Rolland
  • Masson F.
  , 2018.
• 1. Plasma assisted combustion. 2. Plasma of pulsed discharges at high electric field and high specific delivered energies (3 h total)
  
  • Starikovskaia Svetlana
  , 2018.
• Pulsed nanosecond discharges ffat high specific delivered energy
  
  • Starikovskaia Svetlana
  , 2018.
• Signatures of non-local electron heat transport in fusion plasmas.
  
  • Höfler K.
  • Happel T.
  • Hennequin Pascale
  • Ryter F.
  • Stroth U.
  • Asdex Upgrade Team
  , 2018.
• Fundamentals of Low-Temperature Plasma Physics
  
  • Chabert Pascal
  , 2018.
• Plasma Transport in Hall Effect Thrusters
  
  • Chabert Pascal
  • Lafleur Trevor
  • Croes Vivien
  • Martorelli Roberto
  • Tavant Antoine
  • Charoy Thomas
  • Bourdon Anne
  , 2018.
• Anomalous Plasma Transport in Hall Effect Thrusters
  
  • Chabert Pascal
  • Lafleur Trevor
  • Croes Vivien
  • Martorelli Roberto
  • Tavant Antoine
  • Charoy Thomas
  • Bourdon Anne
  , 2018.
• Edge-to-center plasma density ratios in two-dimensional plasma discharges
  
  • Lucken Romain
  • Croes Vivien
  • Lafleur Trevor
  • Raimbault Jean-Luc
  • Bourdon A.
  • Chabert Pascal
  Plasma Sources Science and Technology, IOP Publishing, 2018, 27 (3). Edge-to-center plasma density ratios – so-called h factors – are important parameters for global models of plasma discharges as they are used to calculate the plasma losses at the reactor walls. There are well-established theories for h factors in the one-dimensional case. The purpose of this paper is to establish h factors in two-dimensional (2D) systems, with guidance from a 2D particle-in-cell (PIC) simulation. We derive analytical solutions of a 2D fluid theory that includes the effect of ion inertia, but assumes a constant (independent of space) ion collision frequency (using an average ion velocity) across the discharge. Predicted h factors from this 2D fluid theory have the same order of magnitude and the same trends as the PIC simulations when the average ion velocity used in the collision frequency is set equal to the ion thermal velocity. The best agreement is obtained when the average ion velocity varies with pressure (but remains independent of space), going from half the Bohm velocity at low pressure, to the thermal velocity at high pressure. The analysis also shows that a simple correction of the widely-used 1D heuristic formula may be proposed to accurately incorporate 2D effects. (10.1088/1361-6595/aaaf61)
  DOI : 10.1088/1361-6595/aaaf61
• Coherent Structures and Spectral Energy Transfer in Turbulent Plasma: A Space-Filter Approach
  
  • Camporeale E.
  • Sorriso-Valvo L.
  • Califano F.
  • Retinò Alessandro
  Physical Review Letters, American Physical Society, 2018, 120 (12), pp.125101. Plasma turbulence at scales of the order of the ion inertial length is mediated by several mechanisms, including linear wave damping, magnetic reconnection, the formation and dissipation of thin current sheets, and 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 been presented so far. In the Letter we quantify such a relationship analyzing the results of a two-dimensional high-resolution Hall magnetohydrodynamic 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. (10.1103/PhysRevLett.120.125101)
  DOI : 10.1103/PhysRevLett.120.125101
• Morphologies du champ ionosphérique et sa relation avec la position du foyer du système de courant Sq
  
  • Anad Fatma
  • Amory-Mazaudier Christine
  • Bourouis S.
  • Abtout A.
  • Mazari A.
  • Hamoudi M.
  , 2018.
• Why always more efficient and accurate methods to solve Poissons equation are needed for electrostatic PIC and fluid plasma simulations ?
  
  • Bourdon Anne
  , 2018.
• Application of cold plasma in oncology, multidisciplinary experiments, physical, chemical and biological modeling
  
  • Honnorat Bruno
  , 2018. Plasma-medicine is the field of research describing the medical applications of plasmas, mainly at atmospheric pressure. Cold plasmas are a state of matter characterized by the presence of free electrons with a kinetic energy of several electron volts even though the ions and neutrals may be at room temperature. This transient state, apart from thermal equilibrium, produces highly reactive chemical species. The objective of this multidisciplinary work was to evaluate the anti-tumor potential of cold plasmas. Two types of devices have been designed and manufactured by 3D-printing: Dielectric Barrier Discharge and plasma-jets. In-vitro and in-vivo studies were conducted with TC1 and CT26 cell lines. The production of reactive species produced in a liquid exposed to plasma has been studied in order to understand the in-vitro results and to compare the plasma devices with those of other teams. Various plasma devices have been made to study the effect of the energy deposited during the in-vivo treatment of skin and subcutaneous tumors. A device cooled with liquid nitrogen has been developed to limit skin damage induced by heating. Finally, a numerical simulation modeling the heat transfers of tumors and tissues under plasmas exposure enables to quantify the hyperthermia and the associated lesions by validating the model on experimental results. A critical review of in-vivo plasma-medicine studies published in the literature is proposed to evaluate the role of hyperthermia in the therapeutic effects reported.
• Plasma-activation of tap water using DBD for agronomy applications: Identification and quantification of long lifetime chemical species and production/consumption mechanisms
  
  • Judée Florian
  • Simon Stéphane
  • Bailly Christophe
  • Dufour Thierry
  Water Research, IWA Publishing/Elsevier, 2018, 133, pp.47-59. Cold atmospheric plasmas are weakly ionized gases that can be generated in ambient air. They produce energetic species (e.g. electrons, metastables) as well as reactive oxygen species, reactive nitrogen species, UV radiations and local electric field. Their interaction with a liquid such as tap water can hence change its chemical composition. The resulting " plasma-activated liquid " can meet many applications, including medicine and agriculture. Consequently, a complete experimental set of analytical techniques dedicated to the characterization of long lifetime chemical species has been implemented to characterize tap water treated using cold atmospheric plasma process and intended to agronomy applications. For that purpose, colorimetry and acid titrations are performed, considering acid-base equilibria, pH and temperature variations induced during plasma activation. 16 species are quantified and monitored: hydroxide and hydronium ions, ammonia and ammonium ions, orthophosphates, carbonate ions, nitrite and nitrate ions and hydrogen peroxide. The related consumption/production mechanisms are discussed. In parallel, a chemical model of electrical conductivity based on Kohlrausch's law has been developed to simulate the electrical conductivity of the plasma-activated tap water (PATW). Comparing its predictions with experimental measurements leads to a narrow fitting, hence supporting the self-sufficiency of the experimental set, i.e. the fact that all long lifetime radicals of interest present in PATW are characterized. Finally, to evaluate the potential of cold atmospheric plasmas for agriculture applications, tap water has been daily plasma-treated to irrigate lentils seeds. Then, seedlings lengths have been measured and compared with untreated tap water, showing an increase as high as 34.0% and 128.4% after 3 days and 6 days of activation respectively. The interaction mechanisms between plasma and tap water are discussed as well as their positive synergy on agronomic results. (10.1016/j.watres.2017.12.035)
  DOI : 10.1016/j.watres.2017.12.035