Publications

2019

• Étude de la dynamique de la reconnexion magnétique induite par laser de puissance
  
  • Bolanos Simon
  , 2019. Le travail exposé dans le manuscrit s’inscrit dans l’étude de la reconnexion magnétique (MR) induite par laser de haute puissance. L’étude avait pour objectif de comprendre sa dynamique dans diverses conditions (par exemple, en présence d’un champ guide qui est la composante magnétique hors du plan de reconnexion) ou lors du changement du paramètre-bêta (rapport de la pression plasma sur la pression magnétique) du plasma ou en changeant la géométrie de la MR. Pour compléter l'analyse des données expérimentales que j'ai rassemblées à l'aide d'installations laser (LULI, LMJ), nous avons effectué des simulations avec un code hybride PIC. Les résultats sont comparés aux résultats expérimentaux pour mettre en évidence les mécanismes mis en place.Dans un premier temps, je présenterai quelques expériences réalisées avec l’installation LULI2000 dans le but d’enquêter sur la dynamique de la reconnexion magnétique dans une configuration non coplanaire entre deux tores magnétiques induits par deux spots laser proches irradiant des cibles solides. Bien qu’ils soient distincts des plasmas astrophysiques où le paramètre bêta est faible (~ 10^-3 dans la couronne solaire et ~ 1 dans le vent solaire), ces expériences de reconnexion conduites au moyen de laser (où le paramètre-bêta ~ 10) sont intéressantes pour étudier des questions fondamentales en MR telles que l'influence d'un champ guide sur la dynamique de la MR. Nous montrerons notamment qu'avant le déclenchement d’un événement de MR, la présence (1) d'un champ de guide faible, ou (2) d'une composante de champ magnétique hors du plan de forme quadrupolaire peuvent tous les deux fortement modifier la croissance de la MR.Ensuite, nous discuterons des résultats expérimentaux obtenus avec l’installation LMJ/PETAL (France). Cette installation offre la possibilité d'étudier la MR dans un plasma ayant un paramètre-bêta faible en raison de la forte énergie laser qui peut être transmise à la cible, ce qui génère des champs magnétiques plus intenses. Elle offre également la possibilité d’utiliser plusieurs spots d’irradiation laser, ce qui permet d’évaluer l’effet de la reconnexion magnétique dans le contexte de la fusion par confinement inertiel (FCI) où de nombreux lasers irradient la paroi du holhraum. La MR peut en effet jouer un rôle dans l’interaction entre les plasmas produits le long de la paroi du holhraum. Nous montrerons notamment que la présence de plusieurs spots d’irradiation laser mitoyens modifie la MR, par rapport à la présence de seulement deux spots voisins. Le transfert de l'énergie magnétique induite vers le plasma s’en trouve modifié.
• Study of the plasma/wall interaction and erosion on a plasma thruster of low power.
  
  • Tavant Antoine
  , 2019. Electric propulsion systems that accelerate plasma ions are important for the success of spatial missions (GPS, weather forecast, communication, etc.).The Hall effect thruster is one of the most used and efficient technology.However, its conception and optimization is slow and costly, as key processes are still poorly understood, in particular the electron transport and the plasma-wall interaction.In order to study both phenomena, we use a bi-dimensional kinetic simulation.We showed with 2D PIC simulation results that electrons are non-local, as they are absorbed more quickly at the wall compared to the collision frequency.Consequently, we derived a non-isothermal sheath model using a polytropic state law for the electrons that describes more accurately the plasma-wall interaction.The model can be used with and without secondary electron emission.With electron emission, the sheath model can present up to three solutions, explaining the oscillations observed in the simulations.The azimuthal instability observed, responsible for the electron transport, is compared to the dispersion relation of the ion acoustic wave and the electron cyclotron drift instability.We show that, while the first linear stage of the instability is well understood, the saturated quasi-steady-state is affected by particle-wave interactions and non-linear mechanisms that are not included in the dispersion relation.
• Magnetopause study by means of a multi-fluid approach
  
  • Manuzzo Roberto
  , 2019. In this thesis, new methods are presented which are able to obtain a "realistic" multi-fluid analysis of the Earth’s magnetopause. This goal is reached in three main steps. The analysis of spacecraft data acquired across the magnetopause is done by means of new techniques which relax most of the hypotheses usually assumed about the observed plasma structures. These techniques help in disentangling the principal causes of misunderstanding in data interpretations by discerning whether the observed variations are due to the magnetopause motion in the spacecraft frame or due to the purely temporal variations of the magnetopause structure. Optimization techniques help in determining automatically the parameters (thresholds) the methods are dependent by.The spatial profiles feed a new 3fluid analytical model (two ion and one electron populations) able to spatially confine the magnetospheric and magnetosheath plasmas in their own regions and letting them to partially overlap close to the contact boundary. This model helps also in determining the two ions contributions to the total ion population where this information is not accessible analyzing the distribution functions. The 3fluid equilibrium computed by the analytical model is then perturbed and evolved in time by means of a new 3fluid numerical code, explicitly coded to take the 3fluid model outputs as inputs. The numerical model of the magnetopause develops a magnetic reconnection instability, in agreement to what is observed close to the analyzed magnetopause crossing and leads to conclusions about the spatial distribution of the mixing processes.
• Alfvénic Velocity Spikes and Rotational Flows in the Near-Sun Solar Wind
  
  • Kasper Justin C.
  • Bale Stuart D.
  • Belcher John W.
  • Berthomier Matthieu
  • Case Anthony W.
  • Chandran Benjamin D. G.
  • Curtis D.W.
  • Gallagher D.
  • Gary S.P.
  • Golub L.
  • Halekas Jasper S.
  • Ho Georges C.
  • Horbury T.S.
  • Hu Q.
  • Huang J.
  • Klein Kristopher G.
  • Korreck Kelly E.
  • Larson Davin
  • Livi Roberto
  • Maruca Bennett
  • Lavraud Benoit
  • Louarn Philippe
  • Maksimovic Milan
  • Martinović Mihailo
  • Mcginnis D.
  • Pogorelov N. V.
  • Richardson J.D.
  • Skoug R. M.
  • Steinberg J.T.
  • Stevens Michael L.
  • Szabo Adam
  • Velli Marco
  • Whittlesey Phyllis L
  • Wright K. H.
  • Zank Gary P.
  • Macdowall R.J
  • Mccomas David J.
  • Mcnutt, Ralph
  • Pulupa Marc
  • Raouafi Noureddine
  • Schwadron Nathan A.
  Nature, Nature Publishing Group, 2019, 576 (7786), pp.228-231. (10.1038/s41586-019-1813-z)
  DOI : 10.1038/s41586-019-1813-z
• Magnetotail Current Sheet Prior to Magnetic Reconnection
  
  • Alexandrova Alexandra
  • Retino A.
  • Le Contel Olivier
  • Divin A. V.
  • Strangeway R. J.
  • Plaschke F.
  • Gershman D. J.
  • Giles B. L.
  • Lindqvist P. A.
  • Khotyaintsev Y.
  • Ergun R.
  • Fuselier S. A.
  • Nakamura R.
  • Argall M. R.
  • Fischer D.
  • Torbert R. B.
  • Burch J. L.
  , 2019. The onset of magnetic reconnection is one of the crucial and still poorly understood problems. The Magnetospheric Multiscale (MMS) mission provides a unique opportunity for the long-term monitoring the Earth's magnetotail current sheet prior to and during reconnection activity. Using MMS observations of a number of reconnection events in the magnetotail we investigate how the spatial current density profile across the current sheet varies in time before reconnection is initiated. In addition, we study waves in the current sheet on different scales. These waves may help us understand the role of MHD and kinetic instabilities during current sheet breaking.
• Investigation of fundamental mechanisms of CO2 plasmas
  
  • Morillo-Candas Ana-Sofia
  , 2019. The use of non thermal plasmas is one of the most promising paths to efficiently recycle CO2 into more complex organic molecules, such as energy-dense hydrocarbon fuels, and it is compatible with the use of intermittent renewable energy sources. To obtain satisfactory energy yields, it is necessary to properly control the energy transfer processes, including the vibrational energy of the CO2 believed to be beneficial for the CO2 conversion, or the energy stored in electronically excited species. Recombination processes producing CO2 from the dissociation products (the so-called back reaction) must also be prevented. However, despite the extensive literature in the fields of CO2 lasers, atmospheric entry plasmas or CO2 conversion, many of the basic mechanisms essential for the description of CO2 plasmas are still very poorly understood. The objective of this thesis is therefore to perform experiments under sufficiently well controlled conditions to identify and study some of these fundamental mechanisms. Two types of plasma sources, a DC "glow" discharge and a radio frequency (RF) discharge were studied at low pressures (27-1000 Pa) to slow down characteristic times of various processes. Advanced optical diagnostic techniques were used in situ and time-resolved to obtain all the relevant parameters for a complete description of the plasma. The densities and vibrational temperatures of CO2 and CO were measured by infrared absorption spectroscopy (FTIR), giving also insight in back reaction mechanisms. The density and loss frequencies of oxygen atoms were obtained with High Resolution Two photon Absorption Laser Induced Fluorescence (HR-TALIF), actinometry and Cavity Ring Down Spectroscopy (CRDS), while isotopic exchange measurements provided information on the role of O(1D). Most of these techniques were also used to determine the gas temperature showing simultaneously the consistency and accuracy of the different techniques.The experimental results made possible, for instance, the identification of the most accurate cross section for CO2 dissociation by electronic impact or the quantification of the vibratory de-excitation of CO2 by oxygen atoms. The obtained data were also used to validate a 0D kinetic model developed at IST Lisbon, which allowed the validation of the rates for vibration-vibration or vibration-translation energy transfer processes for the low vibrational levels of CO2.Another important part of the work focused on the role of the surfaces on the CO2 plasma kinetics. The O atoms loss processes were found to be dominated by surface recombination, dependent on the temperature of the O atoms near the surface, similarly to a pure O2 plasma. However, it was found that CO2 plasma can passivate SiO2 surfaces, reducing the recombination probability of oxygen atoms at the walls, and making it identical under plasma exposure and in post-discharge, unlike what is observed in O2 plasma. A preliminary comparison with a Monte-Carlo surface model, provides a valuable insight in the surface mechanisms involved. Large specific SiO2 surfaces were found to induce CO2 formation in the surface under high O atom flux regimes, limiting dissociation efficiency, whereas the use of carbon-based surfaces showed an enormous potential to use the oxygen atoms to enhance the final CO2 conversion, demonstrating the key role of the surfaces in the efficiency of the CO2 conversion and the importance of a proper handling of the oxygen atoms. These results are therefore very valuable to understand which materials would be relevant to be used as catalysts to improve CO2 conversion efficiency by plasma.The thesis provides a detailed view on the fundamental mechanisms controlling the kinetics of CO2 plasmas, and the results presented are therefore useful not only for developing more efficient CO2 conversion processes, with or without catalysts, but they are also relevant in fields such as surface treatment using O2/CO2-containing plasmas.
• Champs magnétiques générés par effet dynamo dans les objets astrophysiques en rotation
  
  • Menu Mélissa
  , 2019. L'objectif de cette thèse est d'étudier la génération des champs magnétiques astrophysiques via l'effet dynamo. L’impact d’une rotation globale et d’un champ magnétique moyen imposés simultanément , configuration appropriée notamment aux intérieurs planétaires et stellaires, est au cœur de cette étude. Une attention particulière est portée à la dynamique temporelle du système, ainsi qu’à la topologie du champ généré. Dans le but d’obtenir une vision d’ensemble, plusieurs approches numériques ont été utilisées, du modèle cubique (code TURBO) focalisé sur l’étude de phénomènes locaux jusqu’au modèle sphérique (code PaRoDy) permettant une comparaison plus directe avec les observations. Ces deux types de géométrie se complètent dans la mesure où l’approche locale, moins contraignante, permet d’observer précisément les conséquences d’un paramètre tandis que l’approche globale est soumise à des contraintes plus réalistes, telles que la convection thermique. Le modèle local a révélé une cascade inverse d’hélicité hybride, second invariant de la MHD doublement anisotrope, dont l’intensité dépend de plusieurs paramètres. Celle-ci est plus importante lorsque la polarisation favorisée par le forçage correspond aux ondes magnétostrophiques (polarisation droite). Également, l’angle d’inclinaison entre les axes du champ magnétique et de la rotation joue un rôle prépondérant, en particulier lorsque θ≻35°, valeur pour laquelle le processus à l’origine de la cascade change et l’affaiblit. Enfin, augmenter le nombre de Prandtl magnétique (Pm) mène à un transfert de l’énergie magnétique vers les grandes échelles plus rapide et plus important . L’étude globale montre également le rôle clé de Pm dans la génération du champ à grande échelle. En effet, les nouvelles valeurs explorées montrent que de forts champs dipolaires peuvent être maintenus dans des régimes plus turbulents. Ce comportement spécifique correspond aux dynamos pour lesquelles la force de Lorentz est non négligeable à grande échelle. L’importance relative de l’inertie face aux forces magnétique est décisive dans la topologie du champ observé. Ainsi, la transition d’un régime dipolaire vers un régime multipolaire est retardée par la force de Lorentz, composante essentielle des équilibres de forces en astrophysique. Ces résultats pourrait s’appliquer à divers systèmes, notamment au champ géomagnétique pendant les renversements.
• The electron Boltzmann equation in a wider context
  
  • Bourdon Anne
  , 2019.
• Magnetic Reconnection in Three Dimensions: Modeling and Analysis of Electromagnetic Drift Waves in the Adjacent Current Sheet
  
  • Ergun R.
  • Hoilijoki S.
  • Ahmadi N.
  • Schwartz S.
  • Wilder F.
  • Drake J.
  • Hesse M.
  • Shay M.
  • Ji H.
  • Yamada M.
  • Graham D.
  • Cassak P.
  • Swisdak M.
  • Burch J.
  • Torbert R.
  • Holmes J.
  • Stawarz J.
  • Goodrich K.
  • Eriksson S.
  • Strangeway R.
  • Lecontel O.
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2019, 124 (12), pp.10085-10103. (10.1029/2019JA027275)
  DOI : 10.1029/2019JA027275
• Magnetic Reconnection in Three Dimensions: Observations of Electromagnetic Drift Waves in the Adjacent Current Sheet
  
  • Ergun R.
  • Hoilijoki S.
  • Ahmadi N.
  • Schwartz S.
  • Wilder F.
  • Burch J.
  • Torbert R.
  • Lindqvist P.‐a.
  • Graham D.
  • Strangeway R.
  • Le Contel O.
  • Holmes J.
  • Stawarz J.
  • Goodrich K.
  • Eriksson S.
  • Giles B.
  • Gershman D.
  • Chen L.
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2019, 124 (12), pp.10104-10118. (10.1029/2019JA027228)
  DOI : 10.1029/2019JA027228
• MESSENGER observations of planetary ion characteristics within Kelvin-Helmholtz vortices at Mercury
  
  • Aizawa Sae
  • Raines Jim M.
  • Terada Naoki
  • Delcourt Dominique
  • André Nicolas
  , 2019.
• Observations of Electromagnetic Electron Holes and Evidence of Cherenkov Whistler Emission
  
  • Steinvall Konrad
  • Khotyaintsev Yuri
  • Graham Daniel
  • Vaivads Andris
  • Le Contel Olivier
  • Russell Christopher
  Physical Review Letters, American Physical Society, 2019, 123 (25). (10.1103/PhysRevLett.123.255101)
  DOI : 10.1103/PhysRevLett.123.255101
• Electron‐Scale Magnetic Structure Observed Adjacent to an Electron Diffusion Region at the Dayside Magnetopause
  
  • Hoilijoki S.
  • Ergun R.
  • Schwartz S.
  • Eriksson S.
  • Wilder F.
  • Webster J.
  • Ahmadi N.
  • Le Contel O.
  • Burch J.
  • Torbert R.
  • Strangeway R.
  • Giles B.
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2019, 124 (12), pp.10153-10169. (10.1029/2019JA027192)
  DOI : 10.1029/2019JA027192
• High‐density O + in Earth's outer magnetosphere and its effect on dayside magnetopause magnetic reconnection
  
  • Fuselier S.
  • Mukherjee J.
  • Denton M.
  • Petrinec S.
  • Trattner K.
  • Toledo‐redondo S.
  • André M.
  • Aunai N.
  • Chappell C.
  • Glocer A.
  • Haaland S.
  • Hesse M.
  • Kistler L.
  • Lavraud B.
  • Li W.
  • Moore T.
  • Graham D.
  • Tenfjord P.
  • Dargent J.
  • Vines S.
  • Strangeway R.
  • Burch J.
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2019, 124 (12), pp.10257-10269. (10.1029/2019JA027396)
  DOI : 10.1029/2019JA027396
• Pattern Formation in Low-Pressure Radio-Frequency Plasmas due to a Transport Instability
  
  • Désangles Victor
  • Raimbault Jean-Luc
  • Poyé Alexandre
  • Chabert Pascal
  • Plihon Nicolas
  Physical Review Letters, American Physical Society, 2019, 123 (265001). Pattern formation, observed experimentally in a radio-frequency plasma in annular geometry, and characterized by azimuthal symmetry breaking of the plasma parameters, is reported. The azimuthal modulation increases with increasing pressure in the range 1-300 Pa. These experimental observations are accurately described by a fluid model in which the transport coefficients are computed from a 0D Boltzmann kinetic equation. A linear stability analysis shows that unstable modulations develop at low and intermediate pressures, following an instability mechanism due to an energy transport effect-the instability mechanism lies in the sign of off-diagonal terms for the electron particles and energy fluxes expressed as functions of gradients of the plasma density and the electron temperature. This model is an excellent candidate to explain the occurrence of striations in radio-frequency plasmas. (10.1103/PhysRevLett.123.265001)
  DOI : 10.1103/PhysRevLett.123.265001
• Cusp and Nightside Auroral Sources of O + in the Plasma Sheet
  
  • Kistler L.
  • Mouikis C.
  • Asamura K.
  • Yokota S.
  • Kasahara S.
  • Miyoshi Y.
  • Keika K.
  • Matsuoka A.
  • Shinohara I.
  • Hori T.
  • Kitamura N.
  • Petrinec S.
  • Cohen I.
  • Delcourt Dominique
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2019, 124 (12), pp.10036-10047. Energetic O + outflow is observed from both the dayside cusp and the nightside aurora, but the relative importance of these regions in populating the plasma sheet and ring current is not known. During a storm on 16 July 2017, the Arase and MMS satellites were located in the near-earth and midtail plasma sheet boundary layers (PSBL). During the storm main phase, Arase and MMS both observe O + in the lobe entering the PSBL, followed by a time period with energy-dispersed bursts of tailward-streaming O +. The ions at MMS are at higher energies than at Arase. Trajectory modeling shows that the ions coming in from the lobe are cusp origin, while the more energetic bursty ions are from the nightside aurora. The observed and simulated energies and temporal dispersion are consistent with these sources. Thus, both regions directly contribute O + to the plasma sheet during this storm main phase. Plain Language Summary The magnetosphere is the region of space encompassed by Earth's magnetic field. The plasma trapped in the magnetosphere can come both from the Sun and from the ionosphere, the ionized layer of the atmosphere. The ionospheric contribution to the plasma increases during geomagnetic storms. These ions get energized in the auroral oval and flow out along magnetic field lines. During storms, this outflow can contain a large fraction of O +. There are two particular regions where this O + outflow occurs, one on the dayside and one on the nightside. This study looks at the contribution of O + from these two regions. Two spacecraft in different locations in the magnetosphere during the storm were able to observe the signatures of ions from both regions indicating that both regions are important during the peak of the storm. (10.1029/2019JA027061)
  DOI : 10.1029/2019JA027061
• Experimental determination of cross-sections/reaction rates: Methods and difficulties
  
  • Booth Jean-Paul
  , 2019.
• [Plasma 2020 Decadal] The essential role of multi-point measurements in turbulence investigations: the solar wind beyond single scale and beyond the Taylor Hypothesis
  
  • H. Matthaeus W.
  • Bandyopadhyay R.
  • R. Brown M.
  • Borovsky J.
  • Carbone V.
  • Caprioli D.
  • Chasapis A.
  • Chhiber R.
  • Dasso S.
  • Dmitruk P.
  • del Zanna L.
  • A. Dmitruk P.
  • Franci Luca
  • P. Gary S.
  • L. Goldstein M.
  • Gomez D.
  • Greco A.
  • S. Horbury T.
  • Ji H.
  • C. Kasper J.
  • G. Klein Kristopher
  • Landi S.
  • Li H. M.
  • Malara Francesco
  • A. Maruca B.
  • Mininni P. D.
  • Oughton Sean
  • Papini E.
  • N. Parashar T.
  • Petrosyan Arakel
  • Pouquet A.
  • Retinò Alessandro
  • Roberts Owen W.
  • Ruffolo David
  • Servidio S.
  • Spence H. E.
  • W. Smith C.
  • E. Stawarz J.
  • Tenbarge J.
  • J. Vasquez1 B.
  • Vaivads A.
  • Valentini F.
  • Velli Marco
  • Verdini Andrea
  • Verscharen Daniel
  • Whittlesey Phyllis
  • Wicks R. T.
  • Bruno Roberto
  • Zimbardo G.
  , 2019.
• Electron Scattering by Low-frequency Whistler Waves at Earth’s Bow Shock
  
  • Oka M.
  • Otsuka F.
  • Matsukiyo S.
  • Wilson L.
  • Argall M.
  • Amano T.
  • Phan T.
  • Hoshino M.
  • Contel O. Le
  • Gershman D.
  • Burch J.
  • Torbert R.
  • Dorelli J.
  • Giles B.
  • Ergun R.
  • Russell C. T.
  • Lindqvist P.
  The Astrophysical Journal, American Astronomical Society, 2019, 886 (1), pp.53. (10.3847/1538-4357/ab4a81)
  DOI : 10.3847/1538-4357/ab4a81
• Numerical Derivation of Steady Flows in Visco-resistive Magnetohydrodynamics for JET and ITER-like Geometries with no Symmetry Breaking
  
  • Oueslati H
  • Bonnet T
  • Minesi N
  • Firpo Marie-Christine
  • Salhi A.
  AIP Conference Proceedings, American Institute of Physics, 2019. Plasma rotation proves to have important effects on the improvement of the confinement and on the entrance into the H-mode of improved confinement in tokamaks. To consider this issue, we propose to determine numerically the steady states of the visco-resistive MHD equations including the non-linear (v.∇)v term. We take into account the external electric field in the toroidal direction used to create the toroidal current required in a tokamak to create the poloidal component of the magnetic field. Numerical results in JET and ITER geometries obtained using the finite element programming language FreeFem++ are presented. We consider realistic values of the resistivity η and vary the viscosity, ν, of which the realistic order of magnitude is poorly known. The axisymmetric steady-state visco-resistive MHD equations with symmetric boundary conditions are solved using a continuation method on ν and a Newton-Raphson scheme to handle the nonlinearity. (10.1063/1.5135482)
  DOI : 10.1063/1.5135482
• Challenges and the next transformative steps in understanding plasma turbulence from the perspective of multi-spacecraft measurements
  
  • Chen L.-J.
  • Bessho N.
  • A. Bookbinder Jay
  • Caprioli D.
  • Goldstein M. L.
  • Ji H.
  • K. Jian Lan
  • Karimabadi H.
  • Khotyaintsev Y. V.
  • G. Klein Kristopher
  • Lavraud Benoit
  • Matthaeus W. H.
  • E. Moore Thomas
  • Retinò Alessandro
  • W. Roberts Owen
  • Roytershteyn V.
  • Schiff C.
  • Spence H. E.
  • Stawarz J. E.
  • Tenbarge J.
  • Wang S.
  , 2019.
• Space Weather: Global Navigation Satellite System, Education, Research,Development
  
  • Amory-Mazaudier Christine
  , 2019. The Space Weather is a new scientific discipline that aims to understand holistically the sun-earth system, in order to understand the impact of solar events on new technologies and in particular on the GNSS system. In this presentation, we will discuss the GNSS system and its applications for research, education and development.
• A Study of Fluctuations in Magnetic Cloud‐Driven Sheaths
  
  • Moissard C.
  • Fontaine D.
  • Savoini P.
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2019, 124 (11), pp.8208-8226. Interplanetary coronal mass ejections are at the center of the research on geomagnetic activity. Sheaths, highly fluctuating structures, which can be found in front of fast interplanetary coronal mass ejections, are some of the least known geoeffective solar transients. Using Morlet transforms, we analyzed the magnetic fluctuations in a list of 42 well-identified and isolated magnetic clouds driving a sheath and shock (Masías-Meza et al., 2016, https://doi.org/10.1051/0004-6361/201628571. We studied the fluctuations inside sheaths by defining two quantities: the power and the anisotropy. With a simple statistical approach we found that sheaths, in particular, those driven by a fast magnetic cloud, encountering a highly turbulent solar wind, and forming a high Alfvén Mach number shock have high levels of turbulent energy (∼10 times compared with the solar wind) as well as a low anisotropy (approximately halved compared with the solar wind) of their fluctuations. On the other hand, the effect of the shock angle and plasma beta in the solar wind are less straightforward: If the shock is quasi-parallel or the beta in the solar wind is high, both the turbulent energy in the sheaths and the anisotropy of the fluctuations are reduced; but for quasi-perpendicular shocks or low beta solar wind the turbulent energy and anisotropy can take any value. (10.1029/2019JA026952)
  DOI : 10.1029/2019JA026952
• Particle Energization in Space Plasmas: Towards a Multi-Point, Multi-Scale Plasma Observatory
  
  • Retino A.
  , 2019.
• 2D axial-azimuthal Particle-In-Cell benchmark for low-temperature magnetized plasmas
  
  • Charoy Thomas
  • Boeuf Jean-Pierre
  • Bourdon Anne
  • Carlsson J.A.
  • Chabert Pascal
  • Cuenot Bénédicte
  • Eremin Denis
  • Garrigues Laurent
  • Hara Kentaro
  • Kaganovich Igor
  • Powis Andrew Tasman
  • Smolyakov Andrei
  • Sydorenko D
  • Tavant Antoine
  • Vermorel Olivier
  • Villafana Willca
  , 2019.