Publications

2022

• Physics of E x B staircases
  
  • Dif-Pradalier G.
  • Clairet F.
  • Diamond P. H.
  • Donnel P.
  • Garbet X.
  • Ghendrih V.
  • Grandgirard A.
  • Medvedeva Anna
  • Milovanov A.
  • Sarazin Y.
  • Vermare L.
  , 2022.
• Axisymmetric steady-state flows in tokamak plasmas under the visco-resistive setting
  
  • Firpo M.-C
  • Krupka A
  • Oueslati H
  • Roverc E
  , 2022. Plasma rotation has been recognized as a key ingredient in the confinement properties of heat and particles in tokamak plasmas. Large speeds could, for example, be beneficial in mitigating some deleterious MHD instabilities, such as resistive wall modes and neoclassical tearing modes. Moreover, intrinsic plasma rotation has been reported in various devices and experimental conditions. In modern tokamaks, magnetic field lines are reconstructed in real times using the Grad-Shafranov equation. This amounts to consider that tokamak plasma axisymmetric equilibria are necessarily static. Consequently, intrinsic plasma rotation in this approach is viewed as being only due to turbulence (coming from 3D effects). Montgomery and coworkers were the first to question/relax the zero-flow hypothesis and to consider the steady-state Navier-Stokes equation keeping the diffusive viscous term and the nonlinear (v.grad)v term [1]. Adding Maxwell equations while accounting for the external drives due to the toroidal electric field, necessary to produce the toroidal current, and the toroidal magnetic field, one is left with a closed system of partial differential equations. This problem was reconsidered [2] using the open-source PDE solver FreeFem++ [3] to compute the ensuing axisymmetric steady-state flows in tokamak plasmas under the visco resistive MHD setting. It was shown [4] that the toroidal velocity field is naturally antisymmetric unless either the domain or the boundary conditions violate the up-down symmetry. For up-down symmetric boundary conditions and plasma domain, the computed velocities turn out to be very small with zero net flow [2,4] in agreement with existing results [1]. Imposing external n=0 magnetic perturbations was shown [4] to offer a way to break the natural up-down symmetry of the system and produce a net toroidal flow. Using realistic parameters, numerical results [4] indicate that n=0 perturbations of the magnetic configuration may be used to increase n=0 steady-state speeds and promote tokamak plasma confinement while preserving axisymmetry. Lately, imposing an up-down inhomogeneous heating was also shown to break up-down symmetry and increase axisymmetric steady-state velocities [5]. Yet, there exists interestingly some self-consistent limitation of this effect: a very large temperature gradient becomes less efficient as the self-consistent temperature convection decreases the effective symmetry breaking in the system. Therefore, in the current state of investigation, we do not consider this scenario as the most promising. Purely geometrical symmetry-breaking effects, such as shaping of the plasma cross-section domain [6], appear contrarily as an efficient way to make tokamak plasma rotate up to the desired fractions of Alfvén velocity necessary to stabilize resistive-wall modes [7]. References [1] L. P. Kamp and D. C. Montgomery, Toroidal flows in resistive magnetohydrodynamic steady states, Physics of Plasmas 10, 157–167 (2003). [2] H. Oueslati, T. Bonnet, N. Minesi, M.-C. Firpo, and A. Salhi, Numerical derivation of steady flows in visco- resistive magnetohydrodynamics for JET and ITER-like geometries with no symmetry breaking, AIP Conference Proceedings 2179, 020009 (2019). [3] F. Hecht, New development in freefem++, J. Numer. Math. 20 (3–4), 251–265 (2012). [4] H. Oueslati, M.-C. Firpo, Breaking up-down symmetry with magnetic perturbations in tokamak plasmas: Increase of axisymmetric steady-state velocities, Phys. Plasmas 27, 102501 (2020). [5] E. Roverc'h, H. Oueslati and M.-C. Firpo, Steady- state flows in a visco-resistive magnetohydrodynamic model of tokamak plasmas with inhomogeneous heating, Journal of Plasma Physics 87, 905870217 (2021). [6] A. Krupka, M.-C. Firpo (in preparation). [7] M. Takechi et al., Identification of a low plasma rotation threshold for stabilization of the resistive-wall mode, Phys. Rev. Lett. 98, 055002 (2007).
• The Space Physics Environment Data Analysis System in Python
  
  • Grimes Eric
  • Harter Bryan
  • Hatzigeorgiu Nick
  • Drozdov Alexander
  • Lewis James
  • Angelopoulos Vassilis
  • Cao Xin
  • Chu Xiangning
  • Hori Tomo
  • Matsuda Shoya
  • Jun Chae-Woo
  • Nakamura Satoko
  • Kitahara Masahiro
  • Segawa Tomonori
  • Miyoshi Yoshizumi
  • Le Contel Olivier
  Frontiers in Astronomy and Space Sciences, Frontiers Media, 2022, 9. In this article, we describe the free, open-source Python-based Space Physics Environment Data Analysis System (PySPEDAS), a platform for multi-mission, multi-instrument retrieval, analysis, and visualization of Heliophysics data. PySPEDAS currently contains load routines for data from 23 space missions, as well as a variety of data from ground-based observatories. The load routines are built from a common set of general routines that provide access to datasets in different ways (e.g., downloading and caching CDF files or accessing data hosted on web services), making the process of adding additional datasets simple. In addition to load routines, PySPEDAS contains numerous analysis tools for working with the dataset once it is loaded. We describe how these load routines and analysis tools are built by utilizing other free, open-source Python projects (e.g., PyTplot, cdflib, hapiclient, etc.) to make tools for space and solar physicists that are extremely powerful, yet easy-to-use. After discussing the code in detail, we show numerous examples of code using PySPEDAS, and discuss limitations and future plans. (10.3389/fspas.2022.1020815)
  DOI : 10.3389/fspas.2022.1020815
• Climatology of Nighttime Medium‐Scale Traveling Ionospheric Disturbances at Mid and Low Latitudes Observed by the DEMETER Satellite in the Topside Ionosphere During the Period 2005–2010
  
  • Nguyen Chien-Thang
  • Berthelier Jean-Jacques
  • Petitdidier Monique
  • Amory-Mazaudier Christine
  • Huy Minh Le
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2022, 127 (10), pp.e2022JA030517. Thermal ion measurements from the French Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions micro-satellite have been used to study the climatology of nighttime Medium-scale traveling ionospheric disturbances (MSTIDs) in the topside ionosphere at 650 km altitude during the 6 years of the satellite operation, from 2005 to 2010. This period encompasses the declining phase of solar cycle 23, the deep solar minimum of 2008–2009 and the early rise of solar cycle 24. MSTIDs were detected from the quasi-periodic variations of the density of the dominant ionospheric O+ ions. Mostly present between ∼15° and ∼40° invariant latitudes with a small number of events in equatorial regions, the MSTIDs exhibit, on the average, larger occurrence rates in the Southern hemisphere with a peak in the Eastern Pacific-South America longitude sector. The dependence of MSTID activity on solar activity appears more complex than the previously reported simple anti-correlation. In addition to year-to-year variations, our study has, in particular, put in evidence a noticeable hemispheric asymmetry in the seasonal variations during the deep solar minimum of 2008–2009. These statistical observations provide a remarkable observational support to the key role of sporadic Es layers and the conjugate mapping of the associated electric fields. Yet, improved theoretical and numerical models, taking into account the actual inter-hemispheric differences of the seasonal and solar activity variations of thermospheric and ionospheric processes, are needed for a better understanding of the highly complex MSTID phenomena. (10.1029/2022JA030517)
  DOI : 10.1029/2022JA030517
• Wave turbulence in inertial electron magnetohydrodynamics
  
  • David Vincent
  • Galtier Sébastien
  Journal of Plasma Physics, Cambridge University Press (CUP), 2022, 88 (5), pp.905880509. A wave turbulence theory is developed for inertial electron magnetohydrodynamics (IEMHD) in the presence of a relatively strong and uniform external magnetic field $\boldsymbol {B_0} = B_0 \hat {\boldsymbol {e}}_\|$ . This regime is relevant for scales smaller than the electron inertial length $d_e$ . We derive the kinetic equations that describe the three-wave interactions between inertial whistler or kinetic Alfvén waves. We show that for both invariants, energy and momentum, the transfer is anisotropic (axisymmetric) with a direct cascade mainly in the direction perpendicular ( $\perp$ ) to $\boldsymbol {B_0}$ . The exact stationary solutions (Kolmogorov–Zakharov spectra) are obtained for which we prove the locality. We also found the Kolmogorov constant $C_K \simeq 8.474$ . In the simplest case, the study reveals an energy spectrum in $k_\perp ^{-5/2} k_\|^{-1/2}$ (with k the wavenumber) and a momentum spectrum enslaved to the energy dynamics in $k_\perp ^{-3/2} k_\|^{-1/2}$ . These solutions correspond to a magnetic energy spectrum ${\sim }k_\perp ^{-9/2}$ , which is steeper than the EMHD prediction made for scales larger than $d_e$ . We conclude with a discussion on the application of the theory to space plasmas. (10.1017/S0022377822000976)
  DOI : 10.1017/S0022377822000976
• Climatology of O/N2 Variations at Low- and Mid-Latitudes during Solar Cycles 23 and 24
  
  • Khan Jahanzeb
  • Younas Waqar
  • Khan Majid
  • Amory-Mazaudier Christine
  Atmosphere, MDPI, 2022, 13 (10), pp.1645. We present a study concerning the thermospheric O/N2 variations for the period 2002 to 2020, using the measurements of global ultraviolet imager (GUVI) onboard TIMED satellite. In this regard, monthly averaged O/N2 was computed—using the five quietest days of the month—at low- and mid-latitudes. To find the longitudinal dependence of thermospheric variations, the analysis is further extended to different longitudinal sectors, namely Asia, Africa, and America. We found that the latitudinal and longitudinal O/N2 variations follow the solar activity. These variations, during a high solar activity in northern winter, are found to be always much greater than southern winter and northern summer. The latitudinal and longitudinal variations of O/N2 at low- and mid-latitudes in December solstice are observed to be higher than June solstice counterparts in the northern hemisphere. We also computed the amplitudes of annual and semiannual variations using the bandpass filters. The former variations of O/N2 for low-latitudes do not follow the solar activity in the southern hemisphere. Moreover, these variations are stronger for mid-latitudes as compared with low-latitude regions. Similarly, the annual variations in Asian and African sectors of southern hemisphere do not follow the solar cycle (SC) trends. In the northern hemisphere, the variations are stronger during a solar maximum than in the southern counterpart. The observed semiannual variations are in-phase for both hemispheres; moreover, the corresponding amplitude remains almost the same at low- and mid-latitudes, while the semiannual variations for low-latitudes, and corresponding longitudinal regions, are stronger during a high solar activity. These variations, for mid-latitudes, in African, northern Asian, and southern American sectors do not follow the SC activity. (10.3390/atmos13101645)
  DOI : 10.3390/atmos13101645
• Physique des jets de plasma froid. Étude fondamentale des streamers guidés et applications à l’oncologie
  
  • Decauchy Henri
  , 2022. Les sources à jet de plasma froid présentent un intérêt majeur pour les applications médicales, en particulier en oncologie. De par leurs propriétés chimiques (production d’espèces réactives de l’azote et de l’oxygène), radiatives (rayonnement UV/visible), thermiques et électriques (champ électrique, impulsions de courant), les jets de plasma froid constituent un outil thérapeutique innovant. En amont d’une utilisation clinique, il est nécessaire de comprendre les mécanismes de physique fondamentale qui régissent leur fonctionnement mais aussi de créer des sources ad hoc pour obtenir une efficacité antitumorale significative à partir de modèles tumoraux à pronostic sombre. Cette thèse se positionne donc à l’interface de deux volets : d’une part un volet dédié à la physique des streamers et des sources à jet de plasma froid menée au LPP (Laboratoire de Physique des Plasmas, Paris) et d’autre part un volet dédié à l’oncologie mené au CRSA (Centre de Recherche Saint-Antoine, Paris) et au CRC (Centre de Recherche des Cordeliers, Paris). En un premier temps, cette thèse porte sur une étude fondamentale dédié à la physique de propagation et de contre-propagation des streamers générés dans des jets de plasma, en interaction avec 3 types de cibles métalliques : électrode annulaire à la masse, électrode plane à la masse et électrode grille à potentiel flottant. Ces cibles correspondent à des éléments pouvant être intégrés aux sources à jet de plasma froid en vue d’une utilisation thérapeutique, afin de garantir l’absence de risque électrique et thermique. A l’aide de diagnostics spectroscopiques, électriques et d’imagerie rapide, il a ainsi été possible de mettre en lumière l’existence de streamers négatifs se contre-propageant à des vitesses supérieures à celles des streamers incidents. Un modèle théorique de la contre-propagation a ainsi pu être élaboré. L’ajout d’une électrode grille à potentiel flottant entre la sortie du tube (source plasma) et l’électrode plane à la masse a permis d’identifier un phénomène de périodisation des streamers qui apparaît pour des conditions précises de tension et de distance : N streamers atteignant la grille (avec 1N entre 1 et 6) conduit à un unique streamer transmis atteignant la cible. Sur la base de mesures électriques et optiques, un modèle est proposé pour analyser les paramètres régissant cette périodisation. De cette compréhension approfondie des interactions « streamers-cibles », découle la possibilité de créer des sources à jet de plasma froid en vue de répondre à des applications oncologiques, notamment des catheters plasma utilisables par endoscopie. Deux modèles de tumeurs solides avec un mauvais pronostic ont ainsi été étudiés : le cholangiocarcinome (cancer des voies biliaires) et le cancer bronchique non à petites cellules (cancer du poumon). Dans le cas du cholangiocarcinome, des expériences in vitro ont démontré une efficacité antitumorale élevée, tout en présentant des avantages en termes de sélectivité biologique. Sur la base d’études in vivo menées sur des modèles murins et dans la perspective d’une applicabilité chez l’humain, un cathéter à plasma froid a été utilisé sur deux modèles précliniques : un ERCP trainer et un modèle anatomique post-mortem porcin. Il a ainsi été possible de montrer l’absence de risque électrique et thermique. En parallèle, l’analyse des effets du plasma froid sur le cancer du poumon non à petites cellules a fait l’objet de 9 campagnes in vivo menées sur des modèles murins au cours de cette thèse. Deux sources à plasma présentant des configurations d’électrodes différentes ont été comparées, les deux entrainant systématiquement des inflexions de croissance tumorale importantes (p-valeur < 1e-4). Un effet abscopal a aussi été démontré sur des modèles tumoraux ectopiques.
• Safety factor impact on the radial electric field in gyrokinetic simulations
  
  • Varennes R
  • Peret M
  • Vermare L.
  • Garbet X
  • Sarazin Y
  • Grandgirard V
  • Dif- Pradalier G
  • Gendrih P
  • Donnel P
  , 2022.
• Filament Leg–Leg Reconnection as a Source of Prominent Supra-arcade Downflows
  
  • Dudík Jaroslav
  • Aulanier Guillaume
  • Kašparová Jana
  • Karlický Marian
  • Zemanová Alena
  • Lörinčík Juraj
  • Druckmüller Miloslav
  The Astrophysical Journal Letters, Bristol : IOP Publishing, 2022, 937 (1), pp.L10. We report on the interaction of the legs of the erupting filament of 2012 August 31 and associated prominent supra-arcade downflows (P-SADs) as observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. We employ a number of image processing techniques to enhance weak interacting features. As the filament erupts, both legs stretch outwards. The positive-polarity leg also untwists and splits into two parts. The first part runs into the conjugate (negative-polarity) leg, tearing it apart. The second part then converges into the remnant of the conjugate leg, after which both weaken and finally disappear. All these episodes of interaction of oppositely oriented filament legs are followed by the appearance of P-SADs, seen in the on-disk projection to be shaped as loop tops, along with many weaker SADs. All SADs are preceded by hot supra-arcade downflowing loops. This observed evolution is consistent with the three-dimensional rr–rf (leg–leg) reconnection, where the erupting flux rope reconnects with itself. In our observations, as well as in some models, the reconnection in this geometry is found to be long lasting. It plays a substantial role in the evolution of the flux rope of the erupting filament and leads to prominent SADs. (10.3847/2041-8213/ac8eaf)
  DOI : 10.3847/2041-8213/ac8eaf
• BepiColombo Mio Observations of Low‐Energy Ions During the First Mercury Flyby: Initial Results
  
  • Harada Yuki
  • Aizawa Sae
  • Saito Yoshifumi
  • André Nicolas
  • Persson Moa
  • Delcourt Dominique
  • Hadid L. Z.
  • Fraenz Markus
  • Yokota Shoichiro
  • Fedorov Andréi
  • Miyake Wataru
  • Penou Emmanuel
  • Barthe Alain
  • Sauvaud Jean‐andré
  • Katra Bruno
  • Matsuda Shoya
  • Murakami Go
  Geophysical Research Letters, American Geophysical Union, 2022, 49 (17). • We present initial reports on low energy ion observations during BepiColombo's first Mercury flyby • Mio observed large fluctuations of ion flux with time scales down to a few seconds around the magnetopause and within the magnetosphere • Ion energy spectra obtained in the midnight magnetotail suggest the presence of an unexpectedly dense cold component (10.1029/2022GL100279)
  DOI : 10.1029/2022GL100279
• Transport barrier onset and edge turbulence shortfall in fusion plasmas
  
  • Dif-Pradalier Guilhem
  • Ghendrih Philippe
  • Sarazin Yanick
  • Caschera Elisabetta
  • Clairet Frédéric
  • Camenen Yann
  • Donnel Peter
  • Garbet Xavier
  • Grandgirard Virginie
  • Munschy Yann
  • Vermare Laure
  • Widmer Fabien
  Communications Physics, Nature Research, 2022, 5 (1), pp.229. Magnetic confinement fusion offers the promise of sustainable and safe energy production on Earth. Advanced experimental scenarios exploit the fascinating yet uncommon ability of confined plasmas to bifurcate into states of enhanced performance upon application of additional free energy sources. Self-regulation of small-scale turbulent eddies is essential to accessing these improved regimes. However, after several decades, basic principles for these bifurcations are still largely debated and clarifications from first principles lacking. We show here, computed from the primitive kinetic equations, establishment of a state of improved confinement through self-organisation of plasma microturbulence. Our results highlight the critical role of the interface between plasma and material boundaries and demonstrate the importance of propagation of turbulence activity beyond regions of convective drive. These observations strongly suggest a paradigm shift where the magnetised plasma at the onset of enhanced performance self-organises into a globally critical state, ‘nonlocally’ controlled by fluxes of turbulence activity. (10.1038/s42005-022-01004-z)
  DOI : 10.1038/s42005-022-01004-z
• Transport in Fusion Plasmas: Is the Tail Wagging the Dog?
  
  • Dif-Pradalier Guilhem
  • Ghendrih Philippe
  • Sarazin Yanick
  • Widmer Fabien
  • Camenen Yann
  • Garbet Xavier
  • Gillot Camille
  • Grandgirard Virginie
  • Vermare L.
  , 2022.
• Intrinsic rotation drive in tokamaks: the competition between turbulence and magnetic braking
  
  • Varennes R
  • Garbet X
  • Vermare L.
  • Sarazin Y
  • Dif-Pradalier G
  • Grandgirard V
  • Ghendrih P
  • Donnel P
  • Peret M
  • Obrejan K
  • Bourne E
  , 2022.
• Switchbacks in the Young Solar Wind: Electron Evolution Observed inside Switchbacks between 0.125 au and 0.25 au
  
  • Nair Raaman
  • Halekas Jasper
  • Whittlesey Phyllis
  • Larson Davin
  • Livi Roberto
  • Berthomier Matthieu
  • Kasper Justin
  • Case Anthony
  • Stevens Michael
  • Bale Stuart
  • Macdowall Robert
  • Pulupa Marc
  The Astrophysical Journal, American Astronomical Society, 2022, 936 (2), pp.164. Switchbacks are localized deviations from the nominal Parker spiral field in the solar wind. In this study, we investigate the electron distributions inside switchbacks, focusing primarily on the suprathermal (halo and strahl) populations. We explore electron parameters in relation to the angle of rotation of the magnetic field from radial to determine whether electron distributions observed within switchbacks have any differences from those outside of switchbacks. Our observations reveal several trends in the suprathermal electron populations inside switchbacks. We find that the sunward deficit in the electron velocity distribution function typically observed near the Sun is filled in at larger rotation angles. This results in the suprathermal electron density and heat flux in the antistrahl direction changing from a negative to a positive value. On many days, we also observe a positive correlation between the halo density and rotation angle, and this may suggest that the growth of the halo may fill in the sunward deficit. We also find that strahl distributions have an increased average angular spread at large magnetic field rotation angles. The increase in suprathermal electron flux in the antistrahl direction, and the increase in strahl width, together could suggest that enhanced scattering occurs inside switchbacks. Electron core beta values tend to increase with the magnetic field rotation angle, mainly due to a decrease in magnetic pressure. An increase in electron beta may favor the growth of instabilities inside switchbacks. The Parker Solar Probe observations therefore support an enhanced role for wave–particle interactions in switchbacks. (10.3847/1538-4357/ac88c4)
  DOI : 10.3847/1538-4357/ac88c4
• Characteristic length scales of plasma electrochemical reactors for nanomaterials synthesis
  
  • Pai David Z
  • Chiang Wei-Hung
  • Kurniawan Darwin
  • Caielli Francesca
  • Thyagarajan Karthik
  • Bellet Romain
  • Khereddine Hanane
  • Polprasarn Kasidapa
  • Orrière Thomas
  • Fang Chih-Yi
  • Lin Kai-Sheng
  , 2022. Many approaches to nanomaterials synthesis can require high temperature, strong/toxic reducing agents, or are complex/expensive. The plasma electrochemical reactor (PEC), composed of an atmospheric-pressure plasma with an aqueous electrode, may provide unique physico-chemical conditions that overcome these difficulties because non-equilibrium electrochemistry and nucleation are initiated in solution without additional heating or reducing agents. Indeed, the synthesis of graphene quantum dots (GQD) has been successfully demonstrated by PEC [1,2]. We seek to develop a detailed mechanism of GQD growth, which likely involves complex non-equilibrium plasma chemistry and interactions near the plasma-liquid interface. Up to now, the chemistry of the liquid phase has mainly been inferred from ex situ or volume-averaged measurements. Conventional experimental techniques suffer from a lack of selectivity and/or degradation of dyes, chemical probes, or spin traps/probes introduced into the liquid. Spatial resolution is often poor or inaccessible. To move beyond ex situ techniques, we have developed an in situ multi-diagnostics approach to encompass a wide range of physical and chemical properties at the plasma-water interface. In particular, this platform features in situ spontaneous Raman microspectroscopy, which is advantageous because of its non-intrusiveness, selectivity, versatility, and straightforward calibration. Using a light-sheet technique, we have probed the interfacial region with micron-scale spatial resolution. To gain insight into the effect of the plasma on the solvent, we tracked the Raman spectrum of water. In particular, from the shape of the –OH stretch band, we observe that the plasma weakens the hydrogen bonding network of water near the interface. Also, near the interface, the concentrations of aqueous H2O2 and NO3- both show an excess in concentration relative to the bulk liquid [3]. Similar interfacial layers have been modeled for radical species such as OH but not for long-lived species such as NO3-. Concerning GQDs, we tracked their production via in situ photoluminescence (PL) spectroscopy. The PL intensity reached a maximum at mm depth rather than near the interface. In addition, particle image velocimetry showed that the liquid flow field exhibits a low-velocity zone at this depth. Together, these results provide the fullest description to date of the reaction environment during GQD synthesis. Acknowledgments Financial support: ANR grants ANR-15-CE06-0007-01 and ANR-11-LABX-0017-01, PHC Orchid 40938YL, CNRS-IEA “GRAFMET”. References [1] Orrière, T., Kurniawan, D., Chang, Y. C., Pai, D. Z., & Chiang, W. H. (2020). Nanotechnology 31 (485001). [2] Yang, J. S., Pai, D. Z., & Chiang, W. H. (2019). Carbon 153, 315-319. [3] Pai, D. Z. (2021) J. Phys. D. : Appl. Phys. 54, 355201
• Magnetospheric Multiscale Observations of Waves and Parallel Electric Fields in Reconnecting Current Sheets in the Turbulent Magnetosheath
  
  • Wilder F.
  • Conley M.
  • Ergun R.
  • Newman D.
  • Chasapis A.
  • Ahmadi N.
  • Burch J.
  • Torbert R.
  • Strangeway R.
  • Giles B.
  • Le Contel O.
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2022, 127 (9). (10.1029/2022JA030511)
  DOI : 10.1029/2022JA030511
• Whistler Waves Associated With Electron Beams in Magnetopause Reconnection Diffusion Regions
  
  • Wang Shan
  • Bessho Naoki
  • Graham Daniel
  • Le Contel Olivier
  • Wilder Frederick
  • Khotyaintsev Yuri
  • Genestreti Kevin
  • Lavraud Benoit
  • Choi Seung
  • Burch James
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2022, 127 (9). (10.1029/2022JA030882)
  DOI : 10.1029/2022JA030882
• Local energy transfer and dissipation in incompressible Hall magnetohydrodynamic turbulence: The coarse-graining approach
  
  • Manzini D.
  • Sahraoui Fouad
  • Califano F.
  • Ferrand R.
  Physical Review E, American Physical Society (APS), 2022, 106 (3), pp.035202. (10.1103/PhysRevE.106.035202)
  DOI : 10.1103/PhysRevE.106.035202
• Optical Constants of Titan's haze analogs particles from 3 to 10 μm
  
  • Perrin Zoé
  • Drant Thomas
  • Caurel Enrique Garcia
  • Chatain Audrey
  • Guaitella Olivier
  • Schmitt Bernard
  • Carrasco Nathalie
  , 2022, 16, pp.EPSC2022-435.
• BibHelioTech internship defense
  
  • Dablanc Axel
  • Génot Vincent
  • Hitier Richard
  • de Salabert Camille
  • Barreaux Sabine
  • Cuxac Pascal
  • Leung Dominica
  • Aunai Nicolas
  • Exbrayat Williams
  , 2022. (10.5281/zenodo.6867940)
  DOI : 10.5281/zenodo.6867940
• The Radial Evolution of the Solar Wind as Organized by Electron Distribution Parameters
  
  • Halekas J.
  • Whittlesey P.
  • Larson D.
  • Maksimovic M.
  • Livi R.
  • Berthomier M.
  • Kasper J.
  • Case A.
  • Stevens M.
  • Bale S.
  • Macdowall R.
  • Pulupa M.
  The Astrophysical Journal, American Astronomical Society, 2022, 936 (1), pp.53. Abstract We utilize observations from the Parker Solar Probe (PSP) to study the radial evolution of the solar wind in the inner heliosphere. We analyze electron velocity distribution functions observed by the Solar Wind Electrons, Alphas, and Protons suite to estimate the coronal electron temperature and the local electric potential in the solar wind. From the latter value and the local flow speed, we compute the asymptotic solar wind speed. We group the PSP observations by asymptotic speed, and characterize the radial evolution of the wind speed, electron temperature, and electric potential within each group. In agreement with previous work, we find that the electron temperature (both local and coronal) and the electric potential are anticorrelated with wind speed. This implies that the electron thermal pressure and the associated electric field can provide more net acceleration in the slow wind than in the fast wind. We then utilize the inferred coronal temperature and the extrapolated electric + gravitational potential to show that both electric field driven exospheric models and the equivalent thermally driven hydrodynamic models can explain the entire observed speed of the slowest solar wind streams. On the other hand, neither class of model can explain the observed speed of the faster solar wind streams, which thus require additional acceleration mechanisms. (10.3847/1538-4357/ac85b8)
  DOI : 10.3847/1538-4357/ac85b8
• Filamentation of the surface plasma layer during the electrical explosion of conductors in strong magnetic fields
  
  • Oreshkin V.
  • Chaikovsky S.
  • Datsko I.
  • Labetskaya N.
  • Oreshkin E.
  • Ratakhin N.
  • Rousskikh A.
  • Vankevich V.
  • Chuvatin Alexandre
  Journal of Applied Physics, American Institute of Physics, 2022, 132 (8), pp.085902. A model has been considered to describe the development of a surface discharge over a conductor electrically exploding in a strong magnetic field. A simulation performed using this model has shown that in the initial stage of the conductor explosion, a plasma layer of several tens of micrometers thick with an electron temperature of several electronvolts is formed on the metal surface. Based on the theory of small perturbations, the development of thermal filamentation instabilities that form in the surface plasma layer has been analyzed. The characteristic growth rates and wavelengths of these instabilities have been determined. The theoretical results were compared with the results of experiments performed on the ZEBRA generator (providing load currents of amplitude about 1 MA and rise time about 100 ns) and on the MIG generator (providing load currents of amplitude about 2 MA and rise time about 100 ns). For the conditions implemented with these generators, the filamentation model gives rise times of thermal filamentation instabilities of tens of nanoseconds at characteristic wavelengths of the order of 100 μm. These values are in good agreement with experimental data, which indicates the adequacy of both the surface discharge development model and the filamentation model. (10.1063/5.0101059)
  DOI : 10.1063/5.0101059
• VTEC observations of intense geomagnetic storms above Nepal: comparison with satellite data, CODE and IGSG models
  
  • Pandit D.
  • Amory-Mazaudier Christine
  • Fleury Rolland
  • Chapagain N P
  • Adhikari B.
  Indian Journal of Physics, 2022. In each period, there are quiet geomagnetic days and intense geomagnetic stormy days. The VTEC observed during these periods has observed both positive and negative ionospheric storms. We compared VTEC Receiver-Independent Exchange Format (RINEX) observations with the Global Ionospheric Map (GIM), Centre for Orbit Determination in Europe (CODE), and IGS working group (IGSG). We found in RINEX observation of the VTEC a noon bite out profile with predominance of morning and afternoon peaks and a nighttime peak, but this was not noticeable clearly with CODE and IGSG models. The comparison between RINEX TEC, CODE, and IGSG models shows that the GIM model does not estimate RINEX VTEC over Nepal. The disagreement between VTEC CODE/IGSG and VTEC RINEX is important during geomagnetically quiet periods, while there is good agreement between VTEC CODE/IGSG and VTEC RINEX during strong geomagnetic storms. We also find a greater disagreement between the models and the data at the equinoxes when the VTEC is larger. It is, therefore, necessary to introduce data from Nepal stations into the models CODE and IGSG in order to improve them. (10.1007/s12648-022-02441-w)
  DOI : 10.1007/s12648-022-02441-w
• Linking Small-scale Solar Wind Properties with Large-scale Coronal Source Regions through Joint Parker Solar Probe–Metis/Solar Orbiter Observations
  
  • Telloni Daniele
  • Zank Gary
  • Sorriso-Valvo Luca
  • D’amicis Raffaella
  • Panasenco Olga
  • Susino Roberto
  • Bruno Roberto
  • Perrone Denise
  • Adhikari Laxman
  • Liang Haoming
  • Nakanotani Masaru
  • Zhao Lingling
  • Hadid L. Z.
  • Sánchez-Cano Beatriz
  • Verscharen Daniel
  • Velli Marco
  • Grimani Catia
  • Marino Raffaele
  • Carbone Francesco
  • Mancuso Salvatore
  • Biondo Ruggero
  • Pagano Paolo
  • Reale Fabio
  • Bale Stuart
  • Kasper Justin
  • Case Anthony
  • de Wit Thierry Dudok
  • Goetz Keith
  • Harvey Peter
  • Korreck Kelly
  • Larson Davin
  • Livi Roberto
  • Macdowall Robert
  • Malaspina David
  • Pulupa Marc
  • Stevens Michael
  • Whittlesey Phyllis
  • Romoli Marco
  • Andretta Vincenzo
  • Deppo Vania Da
  • Fineschi Silvano
  • Heinzel Petr
  • Moses John
  • Naletto Giampiero
  • Nicolini Gianalfredo
  • Spadaro Daniele
  • Stangalini Marco
  • Teriaca Luca
  • Capobianco Gerardo
  • Capuano Giuseppe
  • Casini Chiara
  • Casti Marta
  • Chioetto Paolo
  • Corso Alain
  • Leo Yara De
  • Fabi Michele
  • Frassati Federica
  • Frassetto Fabio
  • Giordano Silvio
  • Guglielmino Salvo
  • Jerse Giovanna
  • Landini Federico
  • Liberatore Alessandro
  • Magli Enrico
  • Massone Giuseppe
  • Messerotti Mauro
  • Pancrazzi Maurizio
  • Pelizzo Maria
  • Romano Paolo
  • Sasso Clementina
  • Schühle Udo
  • Slemer Alessandra
  • Straus Thomas
  • Uslenghi Michela
  • Volpicelli Cosimo
  • Zangrilli Luca
  • Zuppella Paola
  • Abbo Lucia
  • Auchère Frédéric
  • Cuadrado Regina Aznar
  • Berlicki Arkadiusz
  • Ciaravella Angela
  • Lamy Philippe
  • Lanzafame Alessandro
  • Malvezzi Marco
  • Nicolosi Piergiorgio
  • Nisticò Giuseppe
  • Peter Hardi
  • Solanki Sami
  • Strachan Leonard
  • Tsinganos Kanaris
  • Ventura Rita
  • Vial Jean-Claude
  • Woch Joachim
  • Zimbardo Gaetano
  The Astrophysical Journal, American Astronomical Society, 2022, 935 (2), pp.112. Abstract The solar wind measured in situ by Parker Solar Probe in the very inner heliosphere is studied in combination with the remote-sensing observation of the coronal source region provided by the METIS coronagraph aboard Solar Orbiter. The coronal outflows observed near the ecliptic by Metis on 2021 January 17 at 16:30 UT, between 3.5 and 6.3 R ⊙ above the eastern solar limb, can be associated with the streams sampled by PSP at 0.11 and 0.26 au from the Sun, in two time intervals almost 5 days apart. The two plasma flows come from two distinct source regions, characterized by different magnetic field polarity and intensity at the coronal base. It follows that both the global and local properties of the two streams are different. Specifically, the solar wind emanating from the stronger magnetic field region has a lower bulk flux density, as expected, and is in a state of well-developed Alfvénic turbulence, with low intermittency. This is interpreted in terms of slab turbulence in the context of nearly incompressible magnetohydrodynamics. Conversely, the highly intermittent and poorly developed turbulent behavior of the solar wind from the weaker magnetic field region is presumably due to large magnetic deflections most likely attributed to the presence of switchbacks of interchange reconnection origin. (10.3847/1538-4357/ac8103)
  DOI : 10.3847/1538-4357/ac8103
• Editorial: Interplanetary medium variability as observed in the new era of spacecraft missions
  
  • Alberti Tommaso
  • Hadid Lina
  • Mangano Valeria
  • Sanchez-Cano Beatriz
  Frontiers in Astronomy and Space Sciences, Frontiers Media, 2022, 9. (10.3389/fspas.2022.1002727)
  DOI : 10.3389/fspas.2022.1002727