Publications

2023

• Plasma turbulence within cometary plasma environments
  
  • Pucci Francesco
  • Behar Etienne
  • Henri P.
  • Wedlund Cyril Simon
  • Ballerini Giulio
  , 2023. We present a numerical work in which the interaction between a comet and the solar wind is studied in 2D in the plane perpendicular to the solar wind mean field direction. Our simulations are conducted with the hybrid Particle-in-Cell (PIC) code Menura that allows for the injection of a turbulent solar wind [1].First, we consider the case of laminar solar wind and we present a study on the equivalent Mach number of the two-ion-species (cometary and solar wind) plasma surrounding the comet. We develop an expression for the Mach number having suitable limits in the two asymptotic cases of infinite cometary and solar wind ion density; our expression is derived by extending previous studies on bi-ion plasma models [2]. Through numerical simulations in which the cometary activity is varied, we show how our Mach number is able to unambiguously describe the existence and location of the cometary shock.Second, we compare two runs, one with a laminar and one with a turbulent solar wind in the case of moderate cometary activity. We divide the simulation domain into the regions upstream and downstream the cometary shock. We analyze how plasma turbulence properties are affected by the passage through the shock in the case of a turbulent solar wind. Then, we divide the downstream region into three different regions identified by different solar wind-to-cometary ion density ratios. We study the downstream turbulence properties in the case of laminar and turbulent impinging solar wind and how they vary in those regions. [1] Behar, E., Fatemi, S., Henri, P., & Holmström, M. (2022, May). Menura: a code for simulating the interaction between a turbulent solar wind and solar system bodies. In Annales Geophysicae (Vol. 40, No. 3, pp. 281-297). Copernicus GmbH.[2] Dubinin, E. M., Sauer, K., McKenzie, J. F., & Chanteur, G. (2002). Nonlinear waves and solitons propagating perpendicular to the magnetic field in bi-ion plasma with finite plasma pressure. Nonlinear Processes in Geophysics, 9(2), 87-99. (10.5194/egusphere-egu23-9003)
  DOI : 10.5194/egusphere-egu23-9003
• Two classes of magnetotail Dipolarization Fronts observed by MagnetosphericMultiscale Mission: A statistical overview
  
  • Alqeeq Soboh
  • Le Contel Olivier
  • Canu Patrick
  • Retinò Alessandro
  • Chust Thomas
  • Mirioni Laurent
  • Chuvatin Alexandre
  • Nakamura Rumi
  • Ahmadi Narges
  • Wilder Frederick
  • Gershman Daniel
  • Khotyaintsev Yuri
  • Lindqvist Per Arne
  • Ergun Robert
  • Burch James
  • Torbert Roy
  • Fuselier Stephen
  • Russell Christopher
  • Wei Hanying
  • Strangeway Robert
  , 2023. We carried out a statistical study of 132 Dipolarization Fronts (DFs) events detected by the Magnetospheric Multiscale mission (MMS) during the full 2017 Earth’s magnetotail season. We found that two DF classes can be distinguished: class I (74.4%) corresponds to the standard DF properties and energy dissipation whereas a new class II (25.6%), which includes the six DF discussed in S. Alqeeq et al. 2022, corresponds to a bump of the magnetic field associated with a minimum of the ion and electron pressures and a reversal of the energy conversion process. For both classes we found that ions are mostly decoupled from the magnetic field by the Hall fields. The electron pressure gradient term is also contributing to the ion decoupling and likely responsible for an electron decoupling at DF. Both DF classes show that the energy conversion process in the spacecraft frame is driven by the diamagnetic current dominated by the ion pressure gradient. In the fluid frame, it is driven by the electron pressure gradient. In addition, we have shown that the energy conversion processes are not homogeneous at the electron scale mostly due to the variations of the electric fields for both DF classes. (10.5194/egusphere-egu23-7317)
  DOI : 10.5194/egusphere-egu23-7317
• On the Response of the near-Mercury Environment to Different Interplanetary Conditions from full-scale 3D Hybrid Simulations
  
  • Cazzola Emanuele
  • Fontaine Dominique
  • Modolo Ronan
  , 2023. While waiting for further insights from the upcoming data from the BepiColombo mission, this work presents some results from full-scale 3D hybrid (ions kinetic and electrons fluid) computer simulations of the near-Mercury environment under different interplanetary conditions. During its orbit Mercury passes from an high density high magnetic field intensity region (Perihelion) to a low density low magnetic field intensity region (Aphelion). Such environment change drastically influences the response of its magnetic environment, including the stand-off distance of both Bow-Shock and Magnetopause. Being these latter not distant from each other nor from the Hermean exosphere, such a dynamics may lead to important interactions between the planetary and interplanetary environments, as well as lead to unpredictable scenarios whenever the interplanetary conditions occasionally result more extreme than those average values curretly known.Here we aim to give more insights  into the near-Mercury environments under more significant interplanetary conditions by means of full-scale 3D multi-species hybrid simulations, including the Aphelion and Perihelion conditions known to date, as well as more extreme conditions, and compare these results with currently available in-situ observations and recent similar computer simulations.  (10.5194/egusphere-egu23-11568)
  DOI : 10.5194/egusphere-egu23-11568
• The Search-Coil Magnetometer (SCM) of the Radio and Plasma Waves Investigation (RPWI) onboard the ESA JUICE mission
  
  • Retinò Alessandro
  • Mansour Malik
  • Canu Patrick
  • Chust Thomas
  • Hadid Lina
  • Le Contel Olivier
  • Sahraoui Fouad
  • Zouganelis Ioannis
  • Alison Dominique
  • Ba Nadjirou
  • Jeandet Alexis
  • Mehrez Fatima
  • Mirioni Laurent
  • Piberne Rodrigue
  • Berthod Christophe
  • Geyskens Nicolas
  • Sou Gérard
  • Cecconi Baptiste
  • Bergman Jan
  • Wahlund Jan-Erik
  , 2023. The JUpiter ICy moons Explorer (JUICE) mission is the first large-class (L1) mission of ESA Cosmic Vision. JUICE will be launched in April 2023 with an arrival at Jupiter in 2031 and at least four years making detailed observations of Jupiter’s magnetosphere and of three of its largest moons (Ganymede, Callisto and Europa). The Radio and Plasma Wave Investigation (RPWI) consortium will carry the most advanced set of electric and magnetic fields sensors ever flown in Jupiter’s magnetosphere, which will allow to characterize the radio emission and plasma wave environment of Jupiter and its icy moons. Here we present the scientific objectives and the technical features of the Search Coil Magnetometer (SCM) of RPWI. SCM will provide for the first time three-dimensional measurements of magnetic field fluctuations in the frequency range 0.1 Hz – 20 kHz within Jupiter’s magnetosphere. High sensitivity (~10 fT / √Hz at 1 kHz) will be assured by combining an optimized (20 cm long) magnetic transducer with a low-noise (4 nV / √Hz) ASIC pre-amplifier. Perturbations by the spacecraft are strongly reduced by accommodating SCM at about 10 m away from the spacecraft on the JUICE magnetometer boom. The combination of high sensitivity and high cleanliness of SCM measurements will allow unpreceded studies of electromagnetic fluctuations down to plasma kinetic scales, in particular in key regions such as the magnetopause, the auroral region and the magnetotail current sheet of Ganymede’s own magnetosphere which JUICE will orbit for many months. This will lead to important advances in understanding how fundamental plasma processes such as magnetic reconnection, turbulence and particle energization occur in Jupiter’s plasma environment. (10.5194/egusphere-egu23-7689)
  DOI : 10.5194/egusphere-egu23-7689
• Plasma Observatory ESA M7 candidate mission: unveiling plasma energization and energy transport through multiscale observations
  
  • Marcucci Maria Federica
  • Retinò Alessandro
  • Dunlop Malcolm
  • Forsyth Colin
  • Khotyaintsev Yuri
  • Le Contel Olivier
  • Mann Ian
  • Nakamura Rumi
  • Palmroth Minna
  • Plaschke Ferdinand
  • Soucek Jan
  • Yamauchi Masatoshi
  • Vaivads Andris
  • Valentini Francesco
  , 2023. The Earth's Magnetospheric System is the complex and highly dynamic environment in near-Earth space where plasma gets actively energized and transport of large amounts of energy occurs, due to the interaction of the solar wind with the Earth's magnetic field. Understanding plasma energization and energy transport is an open challenge of space plasma physics, with important implications for space weather science as well as for the understanding of distant astrophysical plasmas. Plasma energization and energy transport are related to fundamental processes such as shocks, magnetic reconnection, turbulence and waves, plasma jets and instabilities, which are at the core of the current space plasma physics research. ESA/Cluster and NASA/MMS four-point constellations, as well as the large-scale multipoint mission NASA/THEMIS, have greatly improved over the last two decades our understanding of plasma processes at individual scales compared to earlier single-point measurements. Despite the large amount of available observations, we still do not fully understand the physical mechanisms which give rise to plasma energization and energy transport. The reason is that the fundamental physical processes governing plasma energization and energy transport operate across multiple scales ranging from the large fluid to the smaller kinetic scales. Here we present the Plasma Observatory (PO) multiscale mission concept which is tailored to study plasma energization and energy transport within the Earth's Magnetospheric System. PO baseline is comprised of one mothercraft (MSC) and six identical smallsat daughtercraft (DSC) in an HEO 8 RE X 18 RE orbit, covering all the key regions of the Magnetospheric System where strong energization and transport occur: the foreshock, bow shock, magnetosheath, magnetopause, magnetotail current sheet, and the transition region. MSC payload provides a complete characterization of electromagnetic fields and plasma particles in a single point with time resolution sufficient to resolve kinetic physics at sub-ion scales. The DSCs have identical payload which is much simpler than on the MSC, yet giving a full characterization of the plasma at the ion and fluid scales. Going beyond Cluster, THEMIS and MMS, PO will permit us to resolve for the first time the coupling between ion and fluid scales as well as the non-planarity and non-stationarity of plasma structures at those scales.  PO is one of the five ESA M7 candidates to be launched around 2037 and is currently undergoing a competitive Phase 0 at ESA for further downselection to Phase A at the end of 2023. (10.5194/egusphere-egu23-9043)
  DOI : 10.5194/egusphere-egu23-9043
• Global 3D simulation of the interaction between a turbulent solar wind and a magnetic dipole
  
  • Behar Etienne
  • Henri P.
  • Ballerini Giulio
  • Pucci Francesco
  • Simon-Wedlund Cyril
  , 2023. Far from an ideal laminar flow, the solar wind impacting planetary magnetospheres contains a spectrum of fluctuations extending to virtually all scales. The study of the effects of such fluctuations on a magnetosphere was until recently lacking a numerical tool which would provide a self-consistent global picture of such an interaction. Using a novel 2-step approach, the open source, hybrid-PIC code Menura is employed to first develop a 3D turbulent cascade in an otherwise homogeneous plasma, to then inject this turbulent solution in a domain containing a permanent dipole. We show how solar wind turbulence is affected by the crossing of the shock, and conversely how the global shape of the magnetosphere is evolving compared to its laminar counterpart. We additionally highlight how transient phenomena and coherent structures are naturally occurring in the foreshock and the sheath due to the local direction of the turbulent magnetic field. (10.5194/egusphere-egu23-12129)
  DOI : 10.5194/egusphere-egu23-12129
• Study of kinetic processes based on MMS/Cluster joint measurements in the vicinity of the plasma sheet boundary layer
  
  • Le Contel Olivier
  • Retino Alessandro
  • Chust Thomas
  • Steinvall Konrad
  • Alqeeq Soboh
  • Baraka Mohammed
  • Canu Patrick
  • Fontaine Dominique
  • Mirioni Laurent
  • Dandouras Iannis
  • Carr Christopher
  • Toledo-Redondo Sergio
  • Fazakerley Andrew
  • Doss Natasha
  • Daly Patrick
  • Kiehas Stefan
  • Nakamura Rumi
  • Khotyaintsev Yuri
  • Wilder Frederick
  • Ahmadi Narges
  , 2023. On 28th of August 2018 at 5:30 UT, MMS and Cluster were located in the magnetotail at about 16 earth radii (RE). They both suddenly crossed plasma interfaces. Located near the post midnight sector, Cluster transitioned from a cold plasma sheet to a hot plasma sheet associated with a quasi-parallel earthward flow 800 km/s whereas MMS, located at 4 RE duskward of Cluster, transitioned from a similar cold plasma sheet to the lobe region via a very short period in a hot plasma sheet associated with a vortex-like signature. At 05:50 UT MMS returned to a hot plasma sheet and also detected a quasi-parallel earthward flow ~ 400 km/s and increased energetic ion and electron fluxes. We use measurements from both missions during this conjunction to describe the possible large scale dynamics of the magnetotail as well as some associated kinetic processes. Energetic particle (>50keV) measurements from the two missions are compared. Furthermore, at ion scales, we investigate the possible role of ion fire-hose instability in the plasma flow reduction. At electron scales, we analyze fast and slow non linear electrostatic waves propagating tailward which are detected in the so called electron boundary layer as well as in the hot plasma sheet. We discuss their possible generation mechanisms and link with the large scale dynamics of the magnetotail. (10.5194/egusphere-egu23-12580)
  DOI : 10.5194/egusphere-egu23-12580
• The role of the number of filaments in the dissociation of CO 2 in dielectric barrier discharges
  
  • Douat Claire
  • Ponduri Srinath
  • Boumans T.
  • Guaitella Olivier
  • Welzel Stefan
  • Carbone Emile
  • Engeln Richard
  Plasma Sources Science and Technology, IOP Publishing, 2023. Abstract An experimental investigation of the dissociation of CO2 in a symmetric pin-to-pin dielectric barrier discharge (DBD) is presented. The reactor geometry allows for an accurate control of the number of filaments (microdischarges) and is used to study the impact of one single filament on the CO2 dissociation. We show the number of filaments per half cycle follows a power-law with as a function of the injected power and does not depend on pressure, flow or other process parameters. It is shown that for pressures between 200 and 700 mbar approximately 0.5 W per filament is required and the charge transferred per filament remains constant at 0.5 nC. Furthermore, the dependence of CO2 conversion on only specific energy input is shown to be valid down to a single filament. Additionally, by using quantum cascade laser (QCL) absorption spectroscopy the absolute number of CO molecules produced per filament is measured and is found to be in the range from 5.1011 to 2.1012. The conversion degree of CO2 into CO is estimated to be lower than 0.1% within a single filament and increases with specific energy input. In the presence of a couple of filaments, the maximum energy efficiency obtained is 25%.
A comparison of the conversion degrees in pin-to-pin DBD and plane-to-plane DBD configuration shows that these two reactor geometries follow the same power law. This means the geometry is not the most important parameter in CO2 dissociation in DBDs, but the specific energy input and thus the number of filaments ignited per unit of time. This result means that the dependence of conversion degree on the specific energy input can be extended to a single filament. This observation leads to the conclusion that the specific energy input appears to be valid as a universal scaling parameter down to very low values.

 (10.1088/1361-6595/acceca)
  DOI : 10.1088/1361-6595/acceca
• Reply to “Comment on Ionospheric and Magnetic Signature of a Space Weather Event on August 2018: CME and HSSWs by Kader et al. (2023)”
  
  • Younas Waqar
  • Khan Majid
  • Ammory-Mazaudier C.
  • Fleury Rolland
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2023, 128 (4), pp.e2022JA030943. We agree with Kader et al. (2023, https://doi.org/10.1029/2022ja030701 ) to the extent that longitudinal axis was flipped, by mistake, in Figure 5a of Younas et al. (2020, https://doi.org/10.1029/2020ja027981 ). However, claiming that this leads to wrong interpretation of main finding of the work is not true. This only affects one sentence in the Result section of Younas et al. (2020, https://doi.org/10.1029/2020ja027981 ). Moreover, the claimed corrected figure of Kader et al. (2023, https://doi.org/10.1029/2022ja030701 ) still has a scaling error which may lead to wrong interpretation of GUVI data. For setting a benchmark for future studies, we propose that either scaling should not be done, or it must be the same for all the considered days. Moreover, Kader et al. (2023, https://doi.org/10.1029/2022ja030701 ) showed that by taking mean of data points leads to different results, which is possible however it cannot be considered as an error in our work. If they believe that their method gives better explanation, they should publish it as an independent article. The statement of Kader et al. (2023, https://doi.org/10.1029/2022ja030701 ) about the error in our TEC data is also exaggerated. The article by Bolaji et al. (2021, https://doi.org/10.1029/2020ja029068 ) provided more insight about latitudinal variations in two sectors and used different GPS stations. Obviously, it is not possible to put all data sets in one study. Hence, stating that Bolaji et al. (2021, https://doi.org/10.1029/2020ja029068 ) found errors in our TEC results is a misleading statement. Although Kader et al. (2023, https://doi.org/10.1029/2022ja030701 ) also pointed out an error in Bolaji et al. (2021, https://doi.org/10.1029/2020ja029068 ), however in their title they only comment about Y20. (10.1029/2022JA030943)
  DOI : 10.1029/2022JA030943
• Potential stratospheric ozone depletion due to iodine injection from small satellites
  
  • Feng Wuhu
  • Plane John M C
  • Chipperfield Martyn P.
  • Saiz-Lopez Alfonso
  • Booth Jean‐paul
  Geophysical Research Letters, American Geophysical Union, 2023, 50 (7), pp.e2022GL102300. We use the 3-D Whole Atmospheric Community Climate Model (WACCM) to investigate stratospheric ozone depletion due to the launch of small satellites (e.g., CubeSats) with an iodine propulsion system. The model considers the injection of iodine from the satellites into the Earth’s thermosphere and suggests a 4-yr timescale for transport of the emissions down to the troposphere. The base case scenario is 40,000 small satellite launches per year into low orbit (100-600 km), which would inject 8 tons I yr-1 above 120 km as I+ ions and increase stratospheric inorganic iodine by ~0.1 part per trillion (pptv). The model shows that this scenario produces a negligible impact on global stratospheric ozone (~0.05 DU column depletion). In contrast, a 100-fold increase in the launch rate, and therefore thermospheric iodine injection, is predicted to result in modelled ozone depletion of up to 14 DU (approximately 2-7%) over the polar regions. (10.1029/2022GL102300)
  DOI : 10.1029/2022GL102300
• Homogeneous dielectric barrier discharge in CO 2
  
  • Bajon C
  • Dap Simon
  • Belinger A
  • Guaitella O
  • Hoder T
  • Naudé Nicolas
  Plasma Sources Science and Technology, IOP Publishing, 2023, 32 (4), pp.045012. Abstract This study investigates dielectric barrier discharges generated in CO 2 at atmospheric pressure. According to the literature, under these conditions, discharges usually work in the filamentary regime. On the contrary, the experimental results reported in the present study demonstrate for the very first time that it is also possible to obtain a diffuse CO 2 discharge under these conditions. The diffuse regime appears to be related to a memory effect mechanism occurring at the dielectric surface. Both the filamentary and diffuse regimes were compared in this work based on electrical measurements coupled with intensified charged coupled device (iCCD) imaging and optical emission spectroscopy. The clear difference between both regimes is discussed. (10.1088/1361-6595/acc9d9)
  DOI : 10.1088/1361-6595/acc9d9
• Separatrix parameters and core performances across WEST L-mode database
  
  • Bourdelle Clarisse
  • Morales Jorge
  • Artaud Jean-François
  • Radenac Tennessee
  • Bucalossi Jérôme
  • Ciraolo Guido
  • Clairet Frédéric
  • Dumont Rémi
  • Fedorczak Nicolas
  • Gil Christophe
  • Goniche Marc
  • Guillemaut Christophe
  • Gunn Jamie
  • Maget Patrick
  • Manas Pierre
  • Ostuni Valeria
  • Pegourié Bernard
  • Peysson Yves
  • Tamain Patrick
  • Vermare Laure
  • Vézinet Didier
  • Grover O.
  • Camenen Yann
  • Gaspar J.
  Nuclear Fusion, IOP Publishing, 2023, 63 (5), pp.056021. WEST database analysis shows a correlation of the recycled neutral source around the separatrix with core performances. This observation questions the causality chain between particle source and turbulent transport up to the core in L-mode, high recycling plasmas, an unavoidable phase of all scenarios. The best core performances correlate with the lowest values of the density at the separatrix $n_{sep}$, similarly to AUG and JET in H-mode [G. Verdoolaege et al 2021 Nucl. Fusion 61 076006]. Reflectometry in the midplane provides $n_{sep}$, while T_sep is inferred by the ‘two-point model’ using Langmuir Probe data on divertor targets. Lower separatrix resistivity does not correlate with better core performances, unlike H-mode observations [T. Eich et al 2020 Nucl. Fusion 60 056016]. As expected in presence of an efficient neutral source due to recycling fluxes, $n_{sep}$ correlates with the D recycled particle flux at the divertor measured by visible spectroscopy. Coherently, at a given controlled central line integrated density $\bar{n}$, lower $n_{sep}$ correlates with larger density gradient around the separatrix as well as larger global density peaking, $\bar{n}$$\langle$n$\rangle$ measured by interferometry. The later correlates as well with lower collisionality in the core, similarly to JET and AUG H-modes [C. Angioni et al 2007 Nucl. Fusion 47 1326]. The correlations reported allow phrasing the subsequent causality question: What is the interplay chain between low neutral recycling at the divertor plates, low density at the separatrix, high density peaking at the separatrix, high global density peaking, higher central temperature, better core energy confinement quality? The causality chain understanding is essential to prepare ITER operation and design DEMO scenarios where the ratio of the divertor leg to the ionization length will be larger and where the pumping efficiency with respect to the vacuum vessel volume will be weaker with respect to actual operating tokamaks. (10.1088/1741-4326/acbfcf)
  DOI : 10.1088/1741-4326/acbfcf
• On the Speed of Interplanetary Shocks Propagating through the Magnetosheath
  
  • Moissard Clément
  • Bernal Axel
  • Savoini Philippe
  • Fontaine Dominique
  • Modolo Ronan
  • David Vincent
  • Michotte de Welle Bayane
  , 2023, pp.EGU-9423. Interplanetary shocks are some of the main drivers of geomagnetic storms. Before they can impact the geomagnetic environment, they propagate through the magnetosheath where their properties and geometry can be modified. What is the velocity of interplanetary shocks propagating through the magnetosheath? Previous numerical simulations and observations have given a wide range of apparently contradictory answers to this question, but they seem to all agree that interplanetary shocks generally slow down as they enter the magnetosheath: the interplanetary shocks' velocity in the magnetosheath have been reported to be between 0.25 and 0.93 times their velocity in the solar wind. In this work, we offer two competing simple models to predict the propagation velocity of shocks through the magnetosheath. These models are applied to a list of shocks detected by currently operational spacecraft (e.g. Wind, MMS) as well as to results obtained from a hybrid PIC simulation. We show that our models both reconcile previous results and imply that interplanetary shocks could - in certain space weather-relevant situations - travel faster in the magnetosheath than they did in the solar wind.
• BepiColombo second Mercury flyby : Ion composition measurements from the Mass Spectrum Analyzer (MSA)
  
  • Delcourt Dominique
  • Hadid Lina
  • Saito Yoshifumi
  • Fränz Markus
  • Yokota Shoichiro
  • Fiethe Björn
  • Verdeil Christophe
  • Katra Bruno
  • Leblanc Frédéric
  • Fischer Henning
  • Harada Yuki
  • Fontaine D.
  • Krupp Norbert
  • Michalik Harald
  • Illiano Jean-Marie
  • Berthelier Jean-Jacques
  • Krüger Harald
  • Murakami Go
  • Matsuda Shoya
  , 2023, pp.EGU23-3369. On June 23rd 2022, BepiColombo performed its second gravity assist maneuver (MFB2) at Mercury. Just like the first encounter with Mercury that took place on October 1st 2021, the spacecraft approached the planet from dusk-nightside to dawn-dayside down to an extremely close distance (within about 200 km altitude from the planet surface). Even though BepiColombo is in a so-called “stacked configuration” during cruise, meaning that the instruments cannot be fully operated yet, these instruments can still make interesting observations. Particularly, despite their limited field-of-view, the particle sensors allow us to get a hint on the ion composition and dynamics very close to the planet well before the forthcoming orbit insertion around Mercury in December 2025. In this study, we present observations of the Mass Spectrum Analyzer (MSA) at Mercury during MFB2. MSA is part of the low energy sensors of the Mercury Plasma Particle Experiment (MPPE) consortium (PI: Y. Saito), which is a comprehensive instrumental suite for plasma, high-energy particle and energetic neutral atom measurements (Saito et al., 2021) onboard the Mercury Magnetospheric Orbiter (Mio). MSA is a “reflectron” time-of-flight spectrometer that provides information on the plasma composition and the three-dimensional distribution functions of ions with energies up to ~ 38 keV/q and masses up to ~ 60 amu (Delcourt et al., 2016). In this study, we show that both H+ and He2+ ions in the 1-10 keV range are present throughout the innermost magnetosphere near closest approach. In addition, during this MFB2 sequence, MSA observations provide evidences of He+ ions with energies of several hundreds of eVs. These ions likely originate from the planet exosphere and are rapidly circulated within the magnetosphere. During the outbound sequence of MFB2, MSA measurements also reveal copious amounts of keV protons of solar wind origin that propagate upstream after being reflected from the bow shock. (10.5194/egusphere-egu23-3369)
  DOI : 10.5194/egusphere-egu23-3369
• Experimental study of the edge radial electric field in different drift configurations and its role in the access to H-mode at ASDEX Upgrade
  
  • Plank U.
  • Brida D.
  • Conway G.
  • Happel T.
  • Hubbard A.
  • Pütterich T.
  • Angioni C.
  • Cavedon M.
  • Dux R.
  • Eich T.
  • Fischer R.
  • Hennequin P.
  Physics of Plasmas, American Institute of Physics, 2023, 30 (4). The formation of the equilibrium radial electric field (Er) has been studied experimentally at ASDEX Upgrade (AUG) in L-modes of “favorable” (ion ∇ B-drift toward primary X-point) and “unfavorable” (ion ∇ B-drift away from primary X-point) drift configurations, in view of its impact on H-mode access, which changes with drift configurations. Edge electron and ion kinetic profiles and impurity velocity and mean-field Er profiles across the separatrix are investigated, employing new and improved measurement techniques. The experimental results are compared to local neoclassical theory as well as to a simple 1D scrape-off layer (SOL) model. It is found that in L-modes of matched heating power and plasma density, the upstream SOL Er and the main ion pressure gradient in the plasma edge are the same for either drift configurations, whereas the Er well in the confined plasma is shallower in unfavorable compared to the favorable drift configuration. The contributions of toroidal and poloidal main ion flows to Er, which are inferred from local neoclassical theory and the experiment, cannot account for these observed differences. Furthermore, it is found that in the L-mode, the intrinsic toroidal edge rotation decreases with increasing collisionality and it is co-current in the banana-plateau regime for all different drift configurations at AUG. This gives rise to a possible interaction of parallel Pfirsch–Schlüter flows in the SOL with the confined plasma. Thus, the different H-mode power threshold for the two drift configurations cannot be explained in the same way at AUG as suggested by LaBombard et al. [Phys. Plasmas 12, 056111 (2005)] for Alcator C-Mod. Finally, comparisons of Er profiles in favorable and unfavorable drift configurations at the respective confinement transitions show that also the Er gradients are all different, which indirectly indicates a different type or strength of the characteristic edge turbulence in the two drift configurations. (10.1063/5.0102763)
  DOI : 10.1063/5.0102763
• Les plasmas froids et le Vivant, de nouvelles avancées
  
  • Douat Claire
  • Dufour Thierry
  • Santos Sousa João
  Reflets de la Physique, EDP sciences, 2023 (75), pp.24-30. Depuis le début des années 2000, des avancées technologiques majeures ont permis l'émergence de plasmas froids à pression atmosphérique ayant de faibles valeurs de courant et des températures proches de la température ambiante. Dans cet article, nous exposons dans un premier temps les principales sources de plasma froid utilisées avec succès dans les applications biomédicales, en insistant notamment sur les propriétés physico-chimiques recherchées. Dans un second temps, nous proposons un état de l'art des dernières avancées médicales (en particulier en cancérologie et en dermatologie), ainsi qu'en agriculture. (10.1051/refdp/202375024)
  DOI : 10.1051/refdp/202375024
• Fast magneto-acoustic wave turbulence and the Iroshnikov–Kraichnan spectrum
  
  • Galtier Sébastien
  Journal of Plasma Physics, Cambridge University Press (CUP), 2023, 89 (2), pp.905890205. An analytical theory of wave turbulence is developed for pure compressible magnetohydrodynamics in the small $\beta$ limit. In contrast to previous works where the multiple scale method was not mentioned and slow magneto-acoustic waves were included, we present here a theory for fast magneto-acoustic waves for which only an asymptotic closure is possible in three dimensions. We introduce the compressible Elsässer fields (canonical variables) and show their linear relationship with the mass density and the compressible velocity. The kinetic equations of wave turbulence for three-wave interactions are obtained and the detailed conservation is shown for the two invariants, energy and momentum (cross-helicity). An exact stationary solution (Kolmogorov-Zakharov spectrum) exists only for the energy. We find a $k^{-3/2}$ energy spectrum compatible with the Iroshnikov–Kraichnan (IK) phenomenological prediction; this leads to a mass density spectrum with the same scaling. Despite the presence of a relatively strong uniform magnetic field, this turbulence is characterized by an energy spectrum with a power index that is independent of the angular direction; its amplitude, however, shows an angular dependence. We prove the existence of the IK solution using the locality condition, show that the energy flux is positive and hence the cascade direct and find the Kolmogorov constant. This theory offers a plausible explanation for recent observations in the solar wind at small $\beta$ where isotropic spectra with a $-3/2$ power-law index are found and associated with fast magneto-acoustic waves. This theory may also be used to explain the IK spectrum often observed near the Sun. Besides, it provides a rigorous theoretical basis for the well-known phenomenological IK spectrum, which coincides with the Zakharov–Sagdeev spectrum for acoustic wave turbulence. (10.1017/S0022377823000259)
  DOI : 10.1017/S0022377823000259
• Carbon-Based Composite Microwave Antennas
  
  • Dugin Nikolai
  • Zaboronkova Tatiana
  • Krafft Catherine
  • Belyaev Grigorii
  Electronics, MDPI, 2023, 9 (4), pp.592. Applications of metamaterials to microwave antennas are reviewed over the past decade. The manufacturing of microwave antennas using graphene-containing carbon composite materials was developed and prototypes of dipole and horn antennas made from such materials were created. The radiation properties of the designed antennas and their metal analogs were measured and compared. The standing wave ratios, the radiation patterns and the amplitude-frequency characteristics were analyzed for horn antennas at frequencies 1.6 GHz and 5 GHz and for dipole antennas in the frequency range 0.2–0.6 GHz. The polarization characteristics of the horn antennas were studied. The effects of different carbon composite materials’ structures (fiber or fabric) on the antennas’ parameters were estimated. It is shown that antennas made from graphene-containing composite materials are able to operate efficiently and exhibit almost the same radiation properties as conventional metal antennas of the same geometry and size. However, the carbon-based antennas have much smaller weights and enhanced stability in a wide range of temperatures. In the future, such antennas should replace the conventional ones for many applications, especially for the excitation and reception of electromagnetic waves in space plasmas. (10.3390/electronics9040590)
  DOI : 10.3390/electronics9040590
• Fast O Atom Exchange Diagnosed by Isotopic Tracing as a Probe of Excited States in Nonequilibrium CO 2 –CO–O 2 Plasmas
  
  • Morillo-Candas Ana Sofia
  • Klarenaar Bart
  • Guerra Vasco
  • Guaitella Olivier
  Journal of Physical Chemistry C, American Chemical Society, 2023, 127 (13), pp.6135-6151. (10.1021/acs.jpcc.2c08493)
  DOI : 10.1021/acs.jpcc.2c08493
• Unveiling plasma energization and energy transport with multi-scale observations in the Earth’s Magnetospheric System: the Plasma Observatory ESA M7 candidate mission
  
  • Retino A.
  , 2023.
• Discussion on the transport processes in electrons with non-Maxwellian energy distribution function in partially-ionized plasmas
  
  • Alvarez Laguna Alejandro
  • Esteves B
  • Raimbault J-L
  • Bourdon A
  • Chabert P
  Plasma Physics and Controlled Fusion, IOP Publishing, 2023, 65 (5), pp.054002. Abstract In a previous work (Alvarez Laguna et al 2022 Phys. Plasmas 29 083507), we have developed a non-linear moment model for electrons that self-consistently captures non-Maxwellian electron energy distribution function effects. The model does not rely in the local approximation and the transport coefficients are calculated by expanding the distribution function into Hermite polynomials and by taking moments of the Boltzmann equation, including the collision operator for elastic and inelastic collisions with arbitrary cross sections. This model captures the classical Fick’s, Fourier’s, and Ohm’s law as well as Soret, Dufour, and Peltier effects. In addition, novel non-local transport phenomena appear as a result of spatial gradients of the kurtosis of the distribution function. In this paper, we discuss on the transport effects by analyzing two collisional models: constant collision frequency and constant cross section. We estimate the order of magnitude of the transport processes in non-equilibrium electrons by analyzing the Langmuir probe measurements of a low-pressure argon inductively-coupled discharge. The results show that, under these conditions, the transport produced by the spatial gradients in the kurtosis of the distribution function produces a heat-flux contribution that is of the same order of magnitude as the Fourier and Dufour’s effects. These transport effects are beyond the local field or the electron gradient expansions, commonly used in the low-temperature plasma modeling. (10.1088/1361-6587/acc422)
  DOI : 10.1088/1361-6587/acc422
• An experimental and numerical investigation of the fundamental mechanisms in CO2-CH4 plasmas
  
  • Baratte Edmond
  , 2023. Global warming, a major challenge of this century, is caused by greenhouse gas emissions from human activities, so it is necessary to control these emissions. Recycling CO2 into a value-added product is one solution. Cold plasmas are a promising way to achieve this at low energy cost: the targeted deposition of energy in the molecule limits the loss of energy in heating the gas. A possible recycling track is the Dry Reforming of Methane by plasma, (CO2 + CH4  2CO + 2H2), which allows to produce a mixture of CO and H2 usable in the Fischer-Tropch reaction (nCO + 2n+1 H2  CnH2n+2 + nH2O) to produce heavy carbon chains with high energy density burnable as a conventional fuel.These plasmas are still largely misunderstood because of their complexity: they combine complex physical phenomena with extensive organic chemistry. Plasma processes produce high densities of excited species and highly reactive radicals. Moreover, because of the applicative interest, many studies use inhomogeneous catalysts or configurations (either by the type of discharge or by the reactor geometry), limiting the understanding of the underlying physics. Nevertheless, the optimization of applications requires a good description of the fundamental plasma mechanisms. The question that guides this work is therefore: what are the physical and chemical phenomena leading to the conversion in a CO2-CH4 plasma?Simple and non-intrusive diagnostics based on emission spectroscopy are developed. Actinometry, which measures atomic densities in the plasma, is compared to the Cavity Ring-Down Spectroscopy (CRDS) technique to determine its reliability in O2 and CO2 plasmas. Because of discrepancies in the literature, the accuracy of actinometry is limited, but it provides an order of magnitude of the atomic densities (a key information) and very robust trends. Actinometry as well as the measurement of some gas temperatures can be performed simply with a USB spectrometer.The chemical kinetics of the plasma is studied in a low-pressure glow discharge with Fourier transform infrared spectroscopy, which allows to measure the gas composition. A modelling of the chemical kinetics of the glow discharge is carried out with the kinetic solver LoKI, initially by considering only the molecules with at most 1 carbon atom, using the work previously carried out for the CO2 plasma kinetics. The numerical results are compared to the measurements taken in the glow to constrain the model. Thanks to a good agreement obtained over a wide range of pressures, flows and initial mixtures, the main reaction paths are deduced. Excited species, often neglected in the analysis of CO2-CH4 plasmas, play an essential role, in particular O(1D). Taking into account O(1D) highlights new reaction pathways, usually replaced by the complex chemistry of C2H species. A similar study is carried out by following the temporal evolution of densities in a radiofrequency discharge and adding to the model molecules with 2 carbon atoms. The influence of O(1D) is confirmed, as well as the less preponderant role of C2H compared to the literature. The CH3 + O(1D) reaction appears to be critical. The role of surfaces also appears essential to explain certain processes.Finally, the vibrational kinetics of CO2, crucial to limit the dissociation cost, is studied in 5ms plasma pulses. CH4 and its dissociation products (H2, H2O, H) quench the vibrational excitation of CO2, but CO vibrational excitation is increased in some cases, probably because of the vibrational distribution created by some reactions involving O(1D).
• Complete Genome Sequences of Bioluminescent Staphylococcus aureus Strains Xen31 and Xen36, Derived from Two Clinical Isolates
  
  • Blaise Océane
  • Leseigneur Clarisse
  • Cokelaer Thomas
  • Capuzzo Elena
  • Frescaline Nadira
  • Dussurget Olivier
  Microbiology Resource Announcements, American Society for Microbiology, 2023, 12 (3), pp.e0002423. Here, we report complete genome sequences of two clinical isolates of Staphylococcus aureus , namely, Xen31 and Xen36, which have been genetically modified to express an optimized Photorhabdus luminescens luciferase operon. Xen31 and Xen36 are bioluminescent strains used widely for investigation of bacterial pathogenesis, drug discovery, and development of novel therapies. (10.1128/mra.00024-23)
  DOI : 10.1128/mra.00024-23
• Turbulence characterization during the suppression of edge-localized modes by magnetic perturbations on ASDEX Upgrade
  
  • Leuthold N.
  • Suttrop W.
  • Willensdorfer M.
  • Birkenmeier G.
  • Brida D.
  • Cavedon M.
  • Dunne M.
  • Conway G.D.
  • Fischer R.
  • Gil L.
  • Happel T.
  • Hennequin P.
  • Kappatou A.
  • Kirk A.
  • Manz P.
  • Mcdermott R.M.
  • Vicente J.
  • Zohm H.
  • Upgrade Team The Asdex
  Nuclear Fusion, IOP Publishing, 2023, 63 (4), pp.046014. Abstract We study localized edge turbulence in the ASDEX Upgrade tokamak that appears if resonant magnetic perturbations (RMP) are applied to suppress edge localized modes (ELMs) in the high confinement mode. The concomitant density fluctuations are detected by microwave reflectometry at the outboard midplane. Two modes can be distinguished, (a) a broadband fluctuation below a threshold of the RMP field amplitude, and (b) a narrow-band quasi-coherent mode (QCM) above the threshold. The broadband fluctuation is toroidally spread out but disappears at the toroidal position of maximum E × B shear in the gradient region. Temporal and spatial correlation along field lines of the midplane density fluctuation and the divertor particle flux suggests that this mode is producing significant particle transport across the gradient region and into the divertor, hence contributing to the plasma density reduction that is often observed when applying RMP fields (the so-called ‘pump-out’ effect). The QCM is also toroidally localized, its radial extent grows with increasing RMP field amplitude, and leads to further increased divertor particle flux compared to the broadband mode. Our observations suggest that both modes not only play an important role in keeping the plasma density stationary in the absence of ELMs but also to reduce the plasma pressure such that the plasma edge becomes stable against ELMs. (10.1088/1741-4326/acb1c5)
  DOI : 10.1088/1741-4326/acb1c5
• Deciphering the direct and indirect antitumoral effects of cold atmospheric plasma - application to the cholangiocarcinoma
  
  • Pavy Allan
  • Decauchy Henri
  • Lekbaby Bouchra
  • Soulier Manon
  • Minini Mirko
  • Aoudjehane Lynda
  • El Mourabit Haquima
  • Renault Gilles
  • Camus Marine
  • Pol Jonathan
  • Dufour Thierry
  • Fouassier Laura
  , 2023.