Publications

2020

• The Solar Orbiter Radio and Plasma Waves (RPW) instrument
  
  • Maksimovic M.
  • Bale S. D.
  • Chust Thomas
  • Khotyaintsev Y.
  • Krasnoselskikh V.
  • Kretzschmar M.
  • Plettemeier D.
  • Rucker H. O.
  • Souček J.
  • Steller M.
  • Štverák Š.
  • Trávníček P.
  • Vaivads A.
  • Chaintreuil S.
  • Dekkali M.
  • Alexandrova O.
  • Astier P.-A.
  • Barbary G.
  • Bérard D.
  • Bonnin X.
  • Boughedada K.
  • Cecconi B.
  • Chapron F.
  • Chariet M.
  • Collin C.
  • de Conchy Y.
  • Dias D.
  • Guéguen L.
  • Lamy L.
  • Leray V.
  • Lion, Sonny
  • Malac-Allain L. R.
  • Matteini L.
  • Nguyen Q. N.
  • Pantellini F.
  • Parisot J.
  • Plasson P.
  • Thijs S.
  • Vecchio A.
  • Fratter I.
  • Bellouard E.
  • Lorfèvre E.
  • Danto P.
  • Julien S.
  • Guilhem E.
  • Fiachetti C.
  • Sanisidro J.
  • Laffaye C.
  • Gonzalez F.
  • Pontet B.
  • Quéruel N.
  • Jannet G.
  • Fergeau P.
  • Brochot J.-Y.
  • Cassam-Chenai G.
  • Dudok de Wit T.
  • Timofeeva M.
  • Vincent T.
  • Agrapart C.
  • Delory G. T.
  • Turin P.
  • Jeandet Alexis
  • Leroy P.
  • Pellion J.-C.
  • Bouzid V.
  • Katra Bruno
  • Piberne Rodrigue
  • Recart W.
  • Santolík O.
  • Kolmašová I.
  • Krupař V.
  • Krupařová O.
  • Píša D.
  • Uhlíř L.
  • Lán R.
  • Baše J.
  • Ahlèn L.
  • André M.
  • Bylander L.
  • Cripps V.
  • Cully C.
  • Eriksson A.
  • Jansson S.-E.
  • Johansson E. P. G.
  • Karlsson T.
  • Puccio W.
  • Břínek J.
  • Öttacher H.
  • Panchenko M.
  • Berthomier Matthieu
  • Goetz K.
  • Hellinger P.
  • Horbury T. S.
  • Issautier K.
  • Kontar E.
  • Krucker S.
  • Le Contel Olivier
  • Louarn P.
  • Martinović M.
  • Owen C. J.
  • Retinò Alessandro
  • Rodríguez-Pacheco J.
  • Sahraoui F.
  • Wimmer-Schweingruber R. F.
  • Zaslavsky A.
  • Zouganelis I.
  Astronomy & Astrophysics - A&A, EDP Sciences, 2020, 642, pp.A12. The Radio and Plasma Waves (RPW) instrument on the ESA Solar Orbiter mission is described in this paper. This instrument is designed to measure in-situ magnetic and electric fields and waves from the continuous to a few hundreds of kHz. RPW will also observe solar radio emissions up to 16 MHz. The RPW instrument is of primary importance to the Solar Orbiter mission and science requirements since it is essential to answer three of the four mission overarching science objectives. In addition RPW will exchange on-board data with the other in-situ instruments in order to process algorithms for interplanetary shocks and type III langmuir waves detections. (10.1051/0004-6361/201936214)
  DOI : 10.1051/0004-6361/201936214
• The Solar Orbiter Science Activity Plan
  
  • Zouganelis I.
  • de Groof A.
  • Walsh A.
  • Williams D.
  • Müller D.
  • St Cyr O.
  • Auchère F.
  • Berghmans D.
  • Fludra A.
  • Horbury T.
  • Howard R.
  • Krucker S.
  • Maksimovic M.
  • Owen C.
  • Rodríguez-Pacheco J.
  • Romoli M.
  • Solanki S.
  • Watson C.
  • Sanchez L.
  • Lefort J.
  • Osuna P.
  • Gilbert H.
  • Nieves-Chinchilla T.
  • Abbo L.
  • Alexandrova O.
  • Anastasiadis A.
  • Andretta V.
  • Antonucci E.
  • Appourchaux T.
  • Aran A.
  • Arge C.
  • Aulanier G.
  • Baker D.
  • Bale S.
  • Battaglia M.
  • Bellot Rubio L.
  • Bemporad A.
  • Berthomier Matthieu
  • Bocchialini K.
  • Bonnin X.
  • Brun A.
  • Bruno R.
  • Buchlin E.
  • Büchner J.
  • Bucik R.
  • Carcaboso F.
  • Carr R.
  • Carrasco-Blázquez I.
  • Cecconi B.
  • Cernuda Cangas I.
  • Chen C.
  • Chitta L.
  • Chust T.
  • Dalmasse K.
  • D’amicis R.
  • da Deppo V.
  • de Marco R.
  • Dolei S.
  • Dolla L.
  • Dudok de Wit T.
  • van Driel-Gesztelyi L.
  • Eastwood J.
  • Espinosa Lara F.
  • Etesi L.
  • Fedorov A.
  • Félix-Redondo F.
  • Fineschi S.
  • Fleck B.
  • Fontaine D.
  • Fox N.
  • Gandorfer A.
  • Génot V.
  • Georgoulis M.
  • Gissot S.
  • Giunta A.
  • Gizon L.
  • Gómez-Herrero R.
  • Gontikakis C.
  • Graham G.
  • Green L.
  • Grundy T.
  • Haberreiter M.
  • Harra L.
  • Hassler D.
  • Hirzberger J.
  • Ho G.
  • Hurford G.
  • Innes D.
  • Issautier K.
  • James A.
  • Janitzek N.
  • Janvier M.
  • Jeffrey N.
  • Jenkins J.
  • Khotyaintsev Y.
  • Klein K.-L.
  • Kontar E.
  • Kontogiannis I.
  • Krafft C.
  • Krasnoselskikh V.
  • Kretzschmar M.
  • Labrosse N.
  • Lagg A.
  • Landini F.
  • Lavraud B.
  • Leon I.
  • Lepri S.
  • Lewis G.
  • Liewer P.
  • Linker J.
  • Livi S.
  • Long D.
  • Louarn P.
  • Malandraki O.
  • Maloney S.
  • Martinez-Pillet V.
  • Martinovic M.
  • Masson A.
  • Matthews S.
  • Matteini L.
  • Meyer-Vernet N.
  • Moraitis K.
  • Morton R.
  • Musset S.
  • Nicolaou G.
  • Nindos A.
  • O’brien H.
  • Orozco Suarez D.
  • Owens M.
  • Pancrazzi M.
  • Papaioannou A.
  • Parenti S.
  • Pariat E.
  • Patsourakos S.
  • Perrone D.
  • Peter H.
  • Pinto R.
  • Plainaki C.
  • Plettemeier D.
  • Plunkett S.
  • Raines J.
  • Raouafi N.
  • Reid H.
  • Retinò A.
  • Rezeau L.
  • Rochus P.
  • Rodriguez L.
  • Rodriguez-Garcia L.
  • Roth M.
  • Rouillard A.
  • Sahraoui F.
  • Sasso C.
  • Schou J.
  • Schühle U.
  • Sorriso-Valvo L.
  • Soucek J.
  • Spadaro D.
  • Stangalini M.
  • Stansby D.
  • Steller M.
  • Strugarek Antoine
  • Štverák Š.
  • Susino R.
  • Telloni D.
  • Terasa C.
  • Teriaca L.
  • Toledo-Redondo S.
  • del Toro Iniesta J.
  • Tsiropoula G.
  • Tsounis A.
  • Tziotziou K.
  • Valentini F.
  • Vaivads A.
  • Vecchio A.
  • Velli M.
  • Verbeeck C.
  • Verdini A.
  • Verscharen D.
  • Vilmer Nicole
  • Vourlidas A.
  • Wicks R.
  • Wimmer-Schweingruber R.
  • Wiegelmann T.
  • Young P.
  • Zhukov A.
  Astronomy & Astrophysics - A&A, EDP Sciences, 2020, 642, pp.A3. Solar Orbiter is the first space mission observing the solar plasma both in situ and remotely, from a close distance, in and out of the ecliptic. The ultimate goal is to understand how the Sun produces and controls the heliosphere, filling the Solar System and driving the planetary environments. With six remote-sensing and four in-situ instrument suites, the coordination and planning of the operations are essential to address the following four top-level science questions: (1) What drives the solar wind and where does the coronal magnetic field originate?; (2) How do solar transients drive heliospheric variability?; (3) How do solar eruptions produce energetic particle radiation that fills the heliosphere?; (4) How does the solar dynamo work and drive connections between the Sun and the heliosphere? Maximising the mission's science return requires considering the characteristics of each orbit, including the relative position of the spacecraft to Earth (affecting downlink rates), trajectory events (such as gravitational assist manoeuvres), and the phase of the solar activity cycle. Furthermore, since each orbit's science telemetry will be downloaded over the course of the following orbit, science operations must be planned at mission level, rather than at the level of individual orbits. It is important to explore the way in which those science questions are translated into an actual plan of observations that fits into the mission, thus ensuring that no opportunities are missed. First, the overarching goals are broken down into specific, answerable questions along with the required observations and the so-called Science Activity Plan (SAP) is developed to achieve this. The SAP groups objectives that require similar observations into Solar Orbiter Observing Plans, resulting in a strategic, top-level view of the optimal opportunities for science observations during the mission lifetime. This allows for all four mission goals to be addressed. In this paper, we introduce Solar Orbiter's SAP through a series of examples and the strategy being followed. (10.1051/0004-6361/202038445)
  DOI : 10.1051/0004-6361/202038445
• Solar Wind Turbulence Around Mars: Relation between the Energy Cascade Rate and the Proton Cyclotron Waves Activity
  
  • Andrés Nahuel
  • Romanelli Norberto
  • Hadid L. Z.
  • Sahraoui Fouad
  • Dibraccio Gina
  • Halekas Jasper
  The Astrophysical Journal, American Astronomical Society, 2020, 902 (2), pp.134. (10.3847/1538-4357/abb5a7)
  DOI : 10.3847/1538-4357/abb5a7
• Measurements of Magnetic Field Fluctuations for Plasma Wave Investigation by the Search Coil Magnetometers (SCM) Onboard Bepicolombo Mio (Mercury Magnetospheric Orbiter)
  
  • Yagitani Satoshi
  • Ozaki Mitsunori
  • Sahraoui Fouad
  • Mirioni Laurent
  • Mansour Malik
  • Chanteur Gérard
  • Coillot Christophe
  • Ruocco Sébastien
  • Leray Vincent
  • Hikishima Mitsuru
  • Alison Dominique
  • Le Contel Olivier
  • Kojima Hirotsugu
  • Kasahara Yoshiya
  • Kasaba Yasumasa
  • Sasaki Takashi
  • Yumoto Takahiro
  • Takeuchi Yoshinari
  Space Science Reviews, Springer Verlag, 2020, 216 (7), pp.111. This paper describes the design and performance of the search coil magnetometers (SCM), which are part of the Plasma Wave Investigation (PWI) instrument onboard the BepiColombo/Mio spacecraft (Mercury Magnetospheric Orbiter), which will measure the electric field, plasma waves and radio waves for the first time in Mercury’s plasma environment. The SCM consists of two low-frequency orthogonal search coil sensors (LF-SC) measuring two components of the magnetic field (0.1 Hz – 20 kHz) in the spacecraft spin plane, and a dual-band search coil sensor (DB-SC) picking up the third component along the spin axis at both low-frequencies (LF: 0.1 Hz – 20 kHz) and high-frequencies (HF: 10 kHz – 640 kHz). The DB-SC and the two LF-SC sensors form a tri-axial configuration at the tip of a 4.6-m coilable mast (MAST-SC) extending from the spacecraft body, to minimize artificial magnetic field contamination emitted by the spacecraft electronics. After the successful launch of the spacecraft on 20 October 2018, an initial function check for the SCM was conducted. The nominal function and performance of the sensors and preamplifiers were confirmed, even with the MAST-SC being retracted and stowed in the spacecraft body, resulting in the detection of large interference signals likely from spacecraft electronics. The MAST-SC is scheduled for deployment after the Mercury orbit insertion of Mio in 2025, allowing the SCM to make the first higher frequency measurements of magnetic fluctuations in the Hermean magnetosphere and exosphere, and the local solar wind. These measurements will contribute to the investigation of fundamental problems in the Hermean plasma environment, including turbulence, magnetic reconnection, wave-particle interactions and particle acceleration. (10.1007/s11214-020-00734-2)
  DOI : 10.1007/s11214-020-00734-2
• Comparing Turbulent Cascades and Heating versus Spectral Anisotropy in Solar Wind via Direct Simulations
  
  • Montagud-Camps Victor
  • Grappin Roland
  • Verdini Andrea
  The Astrophysical Journal, American Astronomical Society, 2020, 902 (1), pp.34. In a previous work (MGV18), we showed numerically that the turbulent cascade generated by quasi-2D structures (with wave vectors mostly-perpendicular to the mean magnetic field) is able to generate a temperature profile close to the one observed in solar wind (1/R) in the range 0.2 ≤ R ≤ 1 au. Theory, observations and numerical simulations point to another robust structure, the radial-slab, with dominant wave vectors along the radial: we study here the efficiency of the radial-slab cascade in building the 1/R temperature profile. As in MGV18, we solve the three-dimensional MHD equations including expansion to simulate the turbulent evolution. We find that an isotropic distribution of wave vectors with large cross helicity at 0.2 au, along with a large wind expansion rate, lead again to a temperature decay rate close to 1/R but with a radial-slab anisotropy at 1 au. Surprisingly, the turbulent cascade concentrates in the plane transverse to the radial direction, displaying 1D spectra with scalings close to k −5/3 in this plane. This supports both the idea of turbulent heating of the solar wind, and the existence of two different turbulent cascades, quasi-2D and radial slab, at the origin of the heating. We conclude that sampling the radial spectrum in the solar wind may give but a poor information on the real cascade regime and rate when the radial slab is a non-negligible part of turbulence. (10.3847/1538-4357/abb19e)
  DOI : 10.3847/1538-4357/abb19e
• Coordination of the in situ payload of Solar Orbiter
  
  • Walsh A.
  • Horbury T.
  • Maksimovic M.
  • Owen C.
  • Rodríguez-Pacheco J.
  • Wimmer-Schweingruber R.
  • Zouganelis I.
  • Anekallu C.
  • Bonnin X.
  • Bruno R.
  • Carrasco Blázquez I.
  • Cernuda I.
  • Chust T.
  • de Groof A.
  • Espinosa Lara F.
  • Fazakerley A.
  • Gilbert H.
  • Gómez-Herrero R.
  • Ho G.
  • Krucker S.
  • Lepri S.
  • Lewis G.
  • Livi S.
  • Louarn P.
  • Müller D.
  • Nieves-Chinchilla T.
  • O’brien H.
  • Osuna P.
  • Plasson P.
  • Raines J.
  • Rouillard A.
  • St Cyr O.
  • Sánchez L.
  • Soucek J.
  • Varsani A.
  • Verscharen D.
  • Watson C.
  • Watson G.
  • Williams D.
  Astronomy & Astrophysics - A&A, EDP Sciences, 2020, 642, pp.A5. Solar Orbiter's in situ coordination working group met frequently during the development of the mission with the goal of ensuring that its in situ payload has the necessary level of coordination to maximise science return. Here we present the results of that work, namely how the design of each of the in situ instruments (EPD, MAG, RPW, SWA) was guided by the need for coordination, the importance of time synchronisation, and how science operations will be conducted in a coordinated way. We discuss the mechanisms by which instrument sampling schemes are aligned such that complementary measurements will be made simultaneously by different instruments, and how burst modes are scheduled to allow a maximum overlap of burst intervals between the four instruments (telemetry constraints mean different instruments can spend different amounts of time in burst mode). We also explain how onboard autonomy, inter-instrument communication, and selective data downlink will be used to maximise the number of transient events that will be studied using high-resolution modes of all the instruments. Finally, we briefly address coordination between Solar Orbiter's in situ payload and other missions. (10.1051/0004-6361/201936894)
  DOI : 10.1051/0004-6361/201936894
• Cross‐Scale Quantification of Storm‐Time Dayside Magnetospheric Magnetic Flux Content
  
  • Akhavan‐tafti M.
  • Fontaine D.
  • Slavin J. A
  • Le Contel O.
  • Turner D.
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2020, 125 (10). A clear understanding of storm-time magnetospheric dynamics is essential for a reliable storm forecasting capability. The dayside magnetospheric response to an interplanetary coronal mass ejection (ICME; dynamic pressure P dyn > 20 nPa and storm-time index SYM-H < −150 nT) is investigated using in situ OMNI, Geotail, Cluster, MMS, GOES, Van Allen Probes, and THEMIS measurements. The dayside magnetic flux content is directly quantified from in situ magnetic field measurements at different radial distances. The arrival of the ICME, consisting of shock and sheath regions preceding a magnetic cloud, initiated a storm sudden commencement (SSC) phase (SYM-H~+50 nT). At SSC, the magnetopause standoff distance was compressed earthward at ICME shock encounter at an average rate~−10.8 Earth radii per hour for~10 min, resulting in a rapid 40% reduction in the magnetospheric volume. The "closed" magnetic flux content remained constant at 170 ± 30 kWb inside the compressed dayside magnetosphere, even in the presence of dayside reconnection, as evident by an outsized flux transfer event containing 160 MWb. During the storm main and recovery phases, the magnetosphere expanded. The dayside magnetic flux did not remain constant within the expanding magnetosphere (110 ± 30 kWb), resulting in a 35% reduction in pre-storm flux content during the magnetic cloud encounter. At that stage, the magnetospheric magnetic flux was eroded resulting in a weakened dayside magnetospheric field strength at radial distances R ≥ 5 R E. It is concluded that the inadequate replenishment of the eroded dayside magnetospheric flux during the magnetosphere expansion phase is due to a time lag in storm-time Dungey cycle. Plain Language Summary A clear understanding of Earth's magnetospheric dynamics is essential for a reliable space weather forecasting capability. To achieve this, we take advantage of the Heliophysics System Observatory's (HSO) multitude of in situ observations in order to, for the first time, quantify the amount of magnetic flux stored in the dayside magnetosphere. The stored magnetic flux shields our ground-based and space-borne assets from adverse space weather events. We examine the dayside magnetic flux content during an encounter with an interplanetary coronal mass ejection (ICME). ICME is a large-scale bundle of magnetic flux and charged particles originating from the Sun. Upon arrival, the ICME which occupied nearly one third of the space between the Sun and Earth forced the dayside magnetosphere to rapidly shrink down to geosynchronous orbit where most communications and weather satellites are located. Though the dayside magnetosphere significantly shrunk, its magnetic flux content remained constant. It was only when the dayside magnetosphere started to expand that the dayside magnetospheric flux content gradually reduced by 35%. It is concluded that, during large ICME encounters, the rate at which dayside magnetic flux is transported to the magnetotail is faster than the rate at which magnetic flux is recycled, via a process known as the Dungey cycle. In addition to the observed loss in magnetic flux, this time lag in Dungey cycle can further cause magnetopause shadowing, wherein significant population of magnetospheric charged particles is lost to solar wind. (10.1029/2020JA028027)
  DOI : 10.1029/2020JA028027
• Resonant Whistler‐Electron Interactions: MMS Observations Versus Test‐Particle Simulation
  
  • Behar E.
  • Sahraoui Fouad
  • Berčič L.
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2020, 125 (10). • Characteristic double-branch signatures in the electron Velocity Distribution Function (VDF) are observed simultaneously with a whistler wave. • The wave, applied to test-particles, produces signatures in the VDF through Landau and cyclotron resonances. • This resonant wave-particle interaction cannot be diagnosed in the Magnetospheric MultiScale (MMS) observations through the dissipative E • J term. (10.1029/2020JA028040)
  DOI : 10.1029/2020JA028040
• Breaking up-down symmetry with magnetic perturbations in tokamak plasmas: increase of axisymmetric steady-state velocities
  
  • Oueslati H.
  • Firpo M.-C
  Physics of Plasmas, American Institute of Physics, 2020, 27 (10), pp.102501. Plasma rotation plays a crucial role on heat and particle confinement in tokamaks. To consider this issue, we numerically compute the axisymmetric steady states of the visco-resistive magnetohydrodynamic equations including the non-linear (v · ∇)v term using the finite element method. Imposing external n = 0 magnetic perturbations offers a way to break the natural up-down symmetry of the system and produce a net toroidal flow. Using realistic parameters, some numerical results indicate that n = 0 perturbations of the magnetic configuration may be used to increase n = 0 steady-state speeds and promote tokamak plasma confinement whilst preserving axisymmetry. (10.1063/5.0016566)
  DOI : 10.1063/5.0016566
• The Solar Orbiter Solar Wind Analyser (SWA) suite
  
  • Owen C. J
  • Bruno R.
  • Livi S.
  • Louarn P.
  • Al Janabi K.
  • Allegrini F.
  • Amoros C.
  • Baruah R.
  • Barthe A.
  • Berthomier M.
  • Bordon S.
  • Brockley-Blatt C.
  • Brysbaert C.
  • Capuano G.
  • Collier M.
  • Demarco R.
  • Fedorov A.
  • Ford J.
  • Fortunato V.
  • Fratter I.
  • Galvin A. B
  • Hancock B.
  • Heirtzler D.
  • Kataria D.
  • Kistler L.
  • Lepri S. T
  • Lewis G.
  • Loeffler C.
  • Marty W.
  • Mathon R.
  • Mayall A.
  • Mele G.
  • Ogasawara K.
  • Orlandi M.
  • Pacros A.
  • Penou E.
  • Persyn S.
  • Petiot M.
  • Phillips M.
  • Přech L.
  • Raines J. M
  • Reden M.
  • Rouillard A. P
  • Rousseau A.
  • Rubiella J.
  • Seran H.
  • Spencer A.
  • Thomas J. W
  • Trevino J.
  • Verscharen D.
  • Wurz P.
  • Alapide A.
  • Amoruso L.
  • André N.
  • Anekallu C.
  • Arciuli V.
  • Arnett K. L
  • Ascolese R.
  • Bancroft C.
  • Bland P.
  • Brysch M.
  • Calvanese R.
  • Castronuovo M.
  • Čermák I.
  • Chornay D.
  • Clemens S.
  • Coker J.
  • Collinson G.
  • D’amicis R.
  • Dandouras I.
  • Darnley R.
  • Davies D.
  • Davison G.
  • de Los Santos A.
  • Devoto P.
  • Dirks G.
  • Edlund E.
  • Fazakerley A.
  • Ferris M.
  • Frost C.
  • Fruit G.
  • Garat C.
  • Génot V.
  • Gibson W.
  • Gilbert J. A
  • de Giosa V.
  • Gradone S.
  • Hailey M.
  • Horbury T. S
  • Hunt T.
  • Jacquey C.
  • Johnson M.
  • Lavraud B.
  • Lawrenson A.
  • Leblanc F.
  • Lockhart W.
  • Maksimovic M.
  • Malpus A.
  • Marcucci F.
  • Mazelle C.
  • Monti F.
  • Myers S.
  • Nguyen T.
  • Rodriguez-Pacheco J.
  • Phillips I.
  • Popecki M.
  • Rees K.
  • Rogacki S. A
  • Ruane K.
  • Rust D.
  • Salatti M.
  • Sauvaud J. A
  • Stakhiv M. O
  • Stange J.
  • Stubbs T.
  • Taylor T.
  • Techer J.-D.
  • Terrier G.
  • Thibodeaux R.
  • Urdiales C.
  • Varsani A.
  • Walsh A. P
  • Watson G.
  • Wheeler P.
  • Willis G.
  • Wimmer-Schweingruber R. F
  • Winter B.
  • Yardley J.
  • Zouganelis I.
  Astronomy & Astrophysics - A&A, EDP Sciences, 2020, 642, pp.A16. The Solar Orbiter mission seeks to make connections between the physical processes occurring at the Sun or in the solar corona and the nature of the solar wind created by those processes which is subsequently observed at the spacecraft. The mission also targets physical processes occurring in the solar wind itself during its journey from its source to the spacecraft. To meet the specific mission science goals, Solar Orbiter will be equipped with both remote-sensing and in-situ instruments which will make unprecedented measurements of the solar atmosphere and the inner heliosphere. A crucial set of measurements will be provided by the Solar Wind Analyser (SWA) suite of instruments. This suite consists of an Electron Analyser System (SWA-EAS), a Proton and Alpha particle Sensor (SWA-PAS), and a Heavy Ion Sensor (SWA-HIS) which are jointly served by a central control and data processing unit (SWA-DPU). Together these sensors will measure and categorise the vast majority of thermal and suprathermal ions and electrons in the solar wind and determine the abundances and charge states of the heavy ion populations. The three sensors in the SWA suite are each based on the top hat electrostatic analyser concept, which has been deployed on numerous space plasma missions. The SWA-EAS uses two such heads, each of which have 360° azimuth acceptance angles and ±45° aperture deflection plates. Together these two sensors, which are mounted on the end of the boom, will cover a full sky field-of-view (FoV) (except for blockages by the spacecraft and its appendages) and measure the full 3D velocity distribution function (VDF) of solar wind electrons in the energy range of a few eV to ∼5 keV. The SWA-PAS instrument also uses an electrostatic analyser with a more confined FoV (-24° to +42° × ±22.5° around the expected solar wind arrival direction), which nevertheless is capable of measuring the full 3D VDF of the protons and alpha particles arriving at the instrument in the energy range from 200 eV/q to 20 keV/e. Finally, SWA-HIS measures the composition and 3D VDFs of heavy ions in the bulk solar wind as well as those of the major constituents in the suprathermal energy range and those of pick-up ions. The sensor resolves the full 3D VDFs of the prominent heavy ions at a resolution of 5 min in normal mode and 30 s in burst mode. Additionally, SWA-HIS measures 3D VDFs of alpha particles at a 4 s resolution in burst mode. Measurements are over a FoV of -33° to +66° × ±20° around the expected solar wind arrival direction and at energies up to 80 keV/e. The mass resolution (m/Δm) is > 5. This paper describes how the three SWA scientific sensors, as delivered to the spacecraft, meet or exceed the performance requirements originally set out to achieve the mission's science goals. We describe the motivation and specific requirements for each of the three sensors within the SWA suite, their expected science results, their main characteristics, and their operation through the central SWA-DPU. We describe the combined data products that we expect to return from the suite and provide to the Solar Orbiter Archive for use in scientific analyses by members of the wider solar and heliospheric communities. These unique data products will help reveal the nature of the solar wind as a function of both heliocentric distance and solar latitude. Indeed, SWA-HIS measurements of solar wind composition will be the first such measurements made in the inner heliosphere. The SWA data are crucial to efforts to link the in situ measurements of the solar wind made at the spacecraft with remote observations of candidate source regions. This is a novel aspect of the mission which will lead to significant advances in our understanding of the mechanisms accelerating and heating the solar wind, driving eruptions and other transient phenomena on the Sun, and controlling the injection, acceleration, and transport of the energetic particles in the heliosphere. (10.1051/0004-6361/201937259)
  DOI : 10.1051/0004-6361/201937259
• Correcting TLEs at epoch: Application to the GPS constellation
  
  • Ly Delphine
  • Lucken Romain
  • Giolito Damien
  Journal of Space Safety Engineering, Elsevier, 2020, 7, pp.302 - 306. (10.1016/j.jsse.2020.07.032)
  DOI : 10.1016/j.jsse.2020.07.032
• Numerical study of electron transport in Hall thrusters
  
  • Charoy Thomas
  , 2020. In the last decade, the number of satellites orbiting around Earth has grown exponentially. Thanks to their low propellant consumption, more and more electric thrusters are now used aboard these satellites, with the Hall thrusters being one of the most efficient. From the diversity of applications stems the need of widening the thruster power capabilities. However, due to a lack of knowledge on Hall thruster physics, this scaling is currently done empirically, which limits the efficiency of the newly developed thrusters and increases the development time and cost. To overcome this issue, numerical models can be used but a deeper understanding on key phenomena is still needed, more specifically on the electron anomalous transport which should be self-consistently accounted for to properly capture the discharge behaviour.As this transport is related to the azimuthal electron drift instability, an existing 2D Particle-In-Cell code was further developed to simulate this azimuthal direction along with the axial direction in which the ions are accelerated, producing the thrust. Prior to analyse the discharge behaviour, this code has been verified on a benchmark case, with 6 other PIC codes developed in different international research groups. This simplified case was later used to stress-test previous analytical developments to approximate the instability-enhanced electron-ion friction force which represents the contribution of the azimuthal instabilities to the anomalous transport. Then, the neutral dynamics has been included to capture the full self-consistent behaviour of the discharge. We used an artificial scaling technique, increasing the vacuum permittivity, to relax the PIC stability constraints and speed-up the simulations. Thanks to an efficient code parallelisation, we managed to reduce this scaling factor to a small value, hence simulating a case close to reality. The electron-ion friction force was found to be the main contributor to the anomalous transport throughout the whole low-frequency breathing mode oscillations. Finally, the complex interaction between the breathing mode, the ion-transit time instabilities and the azimuthal electron drift instabilities has been studied, with the formation of long-wavelength structures associated with an enhanced anomalous transport.
• Interaction aerosols - plasma in Titan's ionosphere: effect on the gas phase composition
  
  • Chatain Audrey
  • Carrasco Nathalie
  • Vettier Ludovic
  • Guaitella Olivier
  , 2020, pp.EPSC2020-454. Titan's aerosols start forming in the ionosphere, in a reactive environment hosting electrons, ions and radicals. In this work we study the interaction of the aerosols with the 'carbon free' plasma species. In this objective, analogues of Titan's aerosols (tholins) are exposed to a N2-H2 plasma in the laboratory. A previous work observed modifications on the solid aerosols [1]. Complementarily, this study investigates a possible feedback of the tholins erosion on the gas phase composition. The decrease of ammonia and the formation of carbon-bearing (and especially nitrile-bearing) species is observed by neutral and ion mass spectrometry. We suggest surface processes combining reactions with radicals and ion sputtering to explain these observations.
• Re-analysis of the Cassini RPWS/LP data in Titan's ionosphere: electron density and temperature of four cold electron populations
  
  • Chatain Audrey
  • Wahlund Jan-Erik
  • Shebanits Oleg
  • Hadid Lina Z.
  • Eriksson Anders
  • Morooka Michiko
  • Edberg Niklas J T
  • Carrasco Nathalie
  • Guaitella Olivier
  , 2020, 14, pp.EPSC2020-436. The Cassini Langmuir Probe (LP) data acquired in the ionosphere of Titan are re-analysed to finely study the electron behaviour in the birthplace of Titan's aerosols (900-1200 km). The detailed analysis of the complete Cassini LP dataset below 1200 km (57 flybys) shows the systematic detection of 2 to 4 electron populations, with reproducible characteristics depending on altitude and solar illumination. Their densities and temperatures are deduced from the Orbital Motion Limited theory. Statistical correlations with other quantities measured by Cassini are investigated. We finally discuss the origins of the detected populations, one being possibly emitted by aerosols.
• Electron Inflow Velocities and Reconnection Rates at Earth's Magnetopause and Magnetosheath
  
  • Burch J.
  • Webster J.
  • Hesse M.
  • Genestreti K.
  • Denton R.
  • Phan T.
  • Hasegawa H.
  • Cassak P.
  • Torbert R.
  • Giles B.
  • Gershman D.
  • Ergun R.
  • Russell C.
  • Strangeway R.
  • Le Contel O.
  • Pritchard K.
  • Marshall A.
  • Hwang K.‐j.
  • Dokgo K.
  • Fuselier S.
  • Chen L.‐j.
  • Wang S.
  • Swisdak M.
  • Drake J.
  • Argall M.
  • Trattner K.
  • Yamada M.
  • Paschmann G.
  Geophysical Research Letters, American Geophysical Union, 2020, 47 (17). (10.1029/2020GL089082)
  DOI : 10.1029/2020GL089082
• Automatic Classification of Plasma Regions in Near-Earth Space With Supervised Machine Learning: Application to Magnetospheric Multi Scale 2016–2019 Observations
  
  • Breuillard Hugo
  • Dupuis Romain
  • Retino Alessandro
  • Le Contel Olivier
  • Amaya Jorge
  • Lapenta Giovanni
  Frontiers in Astronomy and Space Sciences, Frontiers Media, 2020, 7. (10.3389/fspas.2020.00055)
  DOI : 10.3389/fspas.2020.00055
• Investigation of Electron Distribution Functions Associated With Whistler Waves at Dipolarization Fronts in the Earth's Magnetotail: MMS Observations
  
  • Grigorenko E.
  • Malykhin A.
  • Shklyar D.
  • Fadanelli S.
  • Lavraud B.
  • Panov E.
  • Avanov L.
  • Giles B.
  • Le Contel O.
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2020, 125 (9). (10.1029/2020JA028268)
  DOI : 10.1029/2020JA028268
• Physical plasma therapy accelerates wound re‐epithelialisation and enhances extracellular matrix formation in cutaneous skin grafts
  
  • Frescaline Nadira
  • Duchesne Constance
  • Favier Maryline
  • Onifarasoaniaina Rachel
  • Guilbert Thomas
  • Uzan Georges
  • Banzet Sébastien
  • Rousseau A.
  • Lataillade Jean‐jacques
  Journal of Pathology, Wiley, 2020, 252 (4), pp.451-464. Skin grafting is a surgical method of cutaneous reconstruction, which provides volumetric replacement in wounds unable to heal by primary intention. Clinically, full‐thickness skin grafts (FTSGs) are placed in aesthetically sensitive and mechanically demanding areas such as the hands, face, and neck. Complete or partial graft failure is the primary complication associated with this surgical procedure. Strategies aimed at improving the rate of skin graft integration will reduce the incidence of graft failure. Cold atmospheric plasma (CAP) is an emerging technology offering innovative clinical applications. The aim of this study was to test the therapeutic potential of CAP to improve wound healing and skin graft integration into the recipient site. In vitro models that mimic wound healing were used to investigate the ability of CAP to enhance cellular migration, a key factor in cutaneous tissue repair. We demonstrated that CAP enhanced the migration of epidermal keratinocytes and dermal fibroblasts. This increased cellular migration was possibly induced by the low dose of reactive oxygen and nitrogen species produced by CAP. Using a mouse model of burn wound reconstructed with a full‐thickness skin graft, we showed that wounds treated with CAP healed faster than did control wounds. Immunohistochemical wound analysis showed that CAP treatment enhanced the expression of the dermal–epidermal junction components, which are vital for successful skin graft integration. CAP treatment was characterised by increased levels of Tgfbr1 mRNA and collagen I protein in vivo, suggesting enhanced wound maturity and extracellular matrix deposition. Mechanistically, we show that CAP induced the activation of the canonical SMAD‐dependent TGF‐β1 pathway in primary human dermal fibroblasts, which may explain the increased collagen I synthesis in vitro. These studies revealed that CAP improved wound repair and skin graft integration via mechanisms involving extracellular matrix formation. CAP offers a novel approach for treating cutaneous wounds and skin grafts (10.1002/path.5546)
  DOI : 10.1002/path.5546
• ESCAPADE: Coordinated multipoint measurements of Mars' unique hybrid magnetosphere
  
  • Lillis Robert
  • Curry Shannon
  • Luhmann Janet
  • Ma Yingjuan
  • Barjatya Aroh
  • Whittlesey Phyllis L
  • Livi Roberto
  • Larson Davin
  • Xu Shaosui
  • Russell Christopher
  • Fowler Christopher
  • Brain David
  • Thiemann Ed
  • Withers Paul
  • Modolo Ronan
  • Harada Yuki
  • Berthomier Matthieu
  , 2020, pp.EPSC2020-511. Multi-spacecraft missions after 2000 (Cluster II, THEMIS, Van Allen Probes, and MMS) have revolutionized our understanding of the causes, patterns and variability of a wide array of plasma phenomena in the terrestrial magnetospheric environment. ESCAPADE is a twin-spacecraft Mars mission concept that will similarly revolutionize our understanding of how solar wind momentum and energy flows throughout Mars" magnetosphere to drive ion and sputtering escape, two processes which have helped shape Mars" climate evolution over solar system history. ESCAPADE will measure magnetic field strength and topology, ion plasma distributions (separated into light and heavy masses), as well as suprathermal electron flows and thermal electron and ion densities, from coordinated elliptical, 200 km x ~7000 km orbits. ESCAPADE are small spacecraft (<150 kg), traveling to Mars via solar electric propulsion as a rideshare with the Psyche metal-asteroid mission in August 2022. ESCAPADE"s strategically-designed 1-year, 2-part scientific campaign of temporally and spatially-separated multipoint measurements within and between the different regions of Mars" diverse plasma environment, will allow the cause-and-effect of solar wind control of ion and sputtering escape to be unraveled for the first time. Figure 1 shows ESCAPADE"s orbits within a hybrid simulation of the solar wind interaction with Mars, where the color scale represents ion velocity, blue lines are magnetic field, while white lines are sample proton trajectories and spacecraft orbits.ESCAPADE is due to complete its preliminary design review in August 2020, thereafter moving toward build, test, integration and launch two years later. We will report on science goals and objectives, mission design challenges, and provide a status update. (10.5194/epsc2020-511)
  DOI : 10.5194/epsc2020-511
• A new look at Oxygen Plasmas – Quantitative Spectroscopy for rigorous testing of models
  
  • Booth Jean-Paul
  , 2020, 74, pp.1. Despite many decades of study, models of discharges in molecular gases still lack accurate data on many key collisional processes, even for such “simple” and ubiquitous gases as O2. Good data is lacking for near-threshold electron-impact dissociation, surface recombination, the role of metastables, of gas heating, of vibrational excitation, of energy transfer and surface thermal accommodation. Direct measurement of the rate constants of individual processes is a fastidious process, where it is even possible. As an alternative approach, we compare comprehensive measurements of internal plasma parameters to simulations for a plasma with relatively simple chemistry, namely a DC positive column discharge in pure O2. This well-characterized, stable and uniform discharge is optimal for experiment-model comparison. Although it has been studied for a very long time, new experimental methods, including synchrotron Vacuum ultraviolet absorption spectroscopy and laser cavity ringdown absorption spectroscopy (CRDS), allow the densities of all the major species (atomic, molecular, in ground and excited states), as well as the gas translational temperature to be measured, with much-improved absolute accuracy, and with time resolution.. Applied to (partially- and fully-) modulated discharges, these measurements provide unprecedented insight into the kinetic processes occurring (in the gas phase and at surfaces), and a profound test of the models. Whereas a model can be adjusted to fit a set of steady state measurements at one given set of operating conditions, trends with pressure and discharge current, and especially the temporal response to current modulation, are much harder to reconcile with an incorrect model. In practice, model failures often result from omission of key processes, or to neglect of their temperature-dependence. With the relatively simple chemistry occurring in pure O2, with measurements of all principal species as well as the gas temperature, it is possible to identify the missing reactions, and even estimate their rates (and/or activation energies) by adjusting the model to fit the measurements
• A NEW LOOK AT OXYGEN PLASMAS -QUANTITATIVE SPECTROSCOPY FOR RIGOROUS TESTING OF MODELS
  
  • Booth Jean-Paul
  • Chatterjee Abhyuday
  • Guaitella Olivier
  • Lopaev Dmitry
  • Zyryanov Sergey
  • Rakhimova Tatyana
  • Voloshin Dmitry
  • de Oliveira Nelson
  • Nahon Laurent
  , 2020.
• N₂-H₂ capacitively coupled radio-frequency discharges at low pressure. Part I. Experimental results: effect of the H₂ amount on electrons, positive ions and ammonia formation.
  
  • Chatain Audrey
  • Jiménez-Redondo Miguel
  • Vettier Ludovic
  • Guaitella Olivier
  • Carrasco Nathalie
  • Alves Luis Lemos
  • Marques Luis Silvino Alves
  • Cernogora Guy
  Plasma Sources Science and Technology, IOP Publishing, 2020, 29 (8), pp.085019. The mixing of N₂ with H₂ leads to very different plasmas from pure N₂ and H₂ plasma discharges. Numerous issues are therefore raised involving the processes leading to ammonia (NH₃) formation. The aim of this work is to better characterize capacitively-coupled radiofrequency plasma discharges in N₂ with few percents of H₂ (up to 5%), at low pressure (0.3 to 1 mbar) and low coupled power (3 to 13 W). Both experimental measurements and numerical simulations are performed. For clarity, we separated the results in two complementary parts. The actual one (first part), presents the details on the experimental measurements, while the second focuses on the simulation, a hybrid model combining a 2D fluid module and a 0D kinetic module. Electron density is measured by a resonant cavity method. It varies from 0.4 to 5.10⁹ cm^-3, corresponding to ionization degrees from 2.10^-8 to 4.10^-7. Ammonia density is quantified by combining IR absorption and mass spectrometry. It increases linearly with the amount of H₂ (up to 3.10¹³ cm^-3 at 5% H₂). On the contrary, it is constant with pressure, which suggests the dominance of surface processes on the formation of ammonia. Positive ions are measured by mass spectrometry. Nitrogen-bearing ions are hydrogenated by the injection of H₂, N₂H⁺ being the major ion as soon as the amount of H₂ is > 1%. The increase of pressure leads to an increase of secondary ions formed by ion/radical – neutral collisions (ex: N₂H⁺, NH₄⁺, H₃⁺), while an increase of the coupled power favors ions formed by direct ionization (ex: N₂⁺, NH₃⁺, H₂⁺). (10.1088/1361-6595/ab9b1a)
  DOI : 10.1088/1361-6595/ab9b1a
• Uptake Mechanism of Acetic Acid onto Natural Gobi Dust
  
  • Wang Xianjie
  • Romanias Manolis
  • Pei Zhehao
  • Rousseau A.
  • Thévenet Frédéric
  ACS Earth and Space Chemistry, ACS, 2020. (10.1021/acsearthspacechem.0c00168)
  DOI : 10.1021/acsearthspacechem.0c00168
• Modeling MMS Observations at the Earth’s Magnetopause with Hybrid Simulations of Alfvénic Turbulence
  
  • Franci Luca
  • Stawarz Julia
  • Papini Emanuele
  • Hellinger Petr
  • Nakamura Takuma
  • Burgess David
  • Landi Simone
  • Verdini Andrea
  • Matteini Lorenzo
  • Ergun Robert
  • Contel Olivier Le
  • Lindqvist Per-Arne
  The Astrophysical Journal, American Astronomical Society, 2020, 898 (2), pp.175. Magnetospheric Multiscale (MMS) observations of plasma turbulence generated by a Kelvin-Helmholtz (KH) event at the Earth's magnetopause are compared with a high-resolution two-dimensional (2D) hybrid direct numerical simulation of decaying plasma turbulence driven by large-scale balanced Alfvénic fluctuations. The simulation, set up with four observation-driven physical parameters (ion and electron betas, turbulence strength, and injection scale), exhibits a quantitative agreement on the spectral, intermittency, and cascade-rate properties with in situ observations, despite the different driving mechanisms. Such agreement demonstrates a certain universality of the turbulent cascade from magnetohydrodynamic to sub-ion scales, whose properties are mainly determined by the selected parameters, also indicating that the KH instability-driven turbulence has a quasi-2D nature. The fact that our results are compatible with the validity of the Taylor hypothesis, in the whole range of scales investigated numerically, suggests that the fluctuations at sub-ion scales might have predominantly low frequencies. This would be consistent with a kinetic Alfvén wave-like nature and/or with the presence of quasi-static structures. Finally, the third-order structure function analysis indicates that the cascade rate of the turbulence generated by a KH event at the magnetopause is an order of magnitude larger than in the ambient magnetosheath. (10.3847/1538-4357/ab9a47)
  DOI : 10.3847/1538-4357/ab9a47
• Longitudinal Responses of the Equatorial/Low‐Latitude Ionosphere Over the Oceanic Regions to Geomagnetic Storms of May and September 2017
  
  • Akala A. O.
  • Oyeyemi E. O.
  • Amaechi P. O.
  • Radicella S. M.
  • Nava B.
  • Amory-Mazaudier Christine
  Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2020, 125 (8). This study presents the longitudinal dependence of responses of the equatorial/low latitude ionosphere over the oceanic regions to geomagnetic storms of 28th May and 8th September, 2017. We investigated the interplanetary origins of the storms. Total Electron Content (TEC) data were obtained from Global Navigation Satellite System stations, located around the oceanic areas in the equatorial/low latitude regions. The Rate of change of TEC Index (ROTI) was used as a proxy for ionospheric irregularities over the study locations. Further, variations of the horizontal component of the Earth's magnetic fields, obtained from ground-based magnetometers were studied. We used ionospheric disturbance currents, polar cap and auroral electrojet indices to monitor the storm-time electric fields. The May, 2017 storm was driven by sheath and magnetic cloud fields, while the September, 2017 storm was driven by sheath fields. We observed a comparative dominance of TEC intensities over the Oceans than over the landlocked areas. Empirically, our results validated a theoretical suggestion of the existence of a dynamic ocean-ionosphere coupling made by Godin et al. [2015]. Prompt Penetration Electric Fields (PPEF) was observed to be a key factor that controls TEC responses to storms. PPEFs caused TEC enhancements, mainly over the Pacific Ocean longitudes during the May, 2017 storm and enhanced TEC over the Atlantic Ocean and the Pacific Oceans longitudes during the September, 2017 storm. These PPEFs triggered irregularities over the Pacific (10.1029/2020JA027963)
  DOI : 10.1029/2020JA027963