Publications

2022 | 2021 | 2020 | 2019

Sont listées ci-dessous, par année, les publications figurant dans l'archive ouverte HAL.

2017

A statistical study of kinetic-size magnetic holes in turbulent magnetosheath: MMS observations
- Huang S. Y.
- Du J. W.
- Sahraoui Fouad
- Yuan Z. G.
- He J. S.
- Zhao J. S.
- Le Contel Olivier
- Breuillard Hugo
- Wang D. D.
- Yu X. D.
- Deng X. H.
- Fu H.S.
- Zhou M.
- Pollock C. J.
- Torbert R. B.
- Russell C. T.
- Burch J. L.
Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2017, 122 (8), pp.8577-8588. Kinetic-size magnetic holes (KSMHs) in the turbulent magnetosheath are statistically investigated using high time resolution data from the MMS mission. The KSMHs with short duration (i.e., < 0.5 s) have their cross section smaller than the ion gyro-radius. Superposed epoch analysis of all events reveals that an increase in the electron density and total temperature, significantly increase (resp. decrease) the electron perpendicular (resp. parallel) temperature, and an electron vortex inside KSMHs. Electron fluxes at ~ 90° pitch angles with selective energies increase in the KSMHs, are trapped inside KSMHs and form the electron vortex due to their collective motion. All these features are consistent with the electron vortex magnetic holes obtained in 2D and 3D particle-in-cell simulations, indicating that the observed KSMHs seem to be best explained as electron vortex magnetic holes. It is furthermore shown that KSMHs are likely to heat and accelerate the electrons. (10.1002/2017JA024415)
DOI : 10.1002/2017JA024415
Examining Coherency Scales, Substructure, and Propagation of Whistler Mode Chorus Elements With Magnetospheric Multiscale (MMS)
- Turner D. L.
- Lee J. H.
- Claudepierre S. G.
- Fennell J. F.
- Blake J. B.
- Jaynes A. N.
- Leonard T.
- Wilder F. D.
- Ergun R. E.
- Baker D. N.
- Cohen I. J.
- Mauk B. H.
- Strangeway R. J.
- Hartley D. P.
- Kletzing C. A.
- Breuillard Hugo
- Le Contel Olivier
- Khotyaintsev Y. V.
- Torbert R. B.
- Allen R. C.
- Burch J. L.
- Santolík O.
Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2017, 122 (11), pp.201-226. Whistler mode chorus waves are a naturally occurring electromagnetic emission observed in Earth's magnetosphere. Here, for the first time, data from NASA's Magnetospheric Multiscale (MMS) mission were used to analyze chorus waves in detail, including the calculation of chorus wave normal vectors, fi>k. A case study was examined from a period of substorm activity around the time of a conjunction between the MMS constellation and NASA's Van Allen Probes mission on 07 April 2016. Chorus wave activity was simultaneously observed by all six spacecraft over a broad range of L shells (5.5 < L < 8.5), magnetic local time (06:00 < MLT < 09:00), and magnetic latitude (-32° < MLAT < -15°), implying a large chorus active region. Eight chorus elements and their substructure were analyzed in detail with MMS. These chorus elements were all lower band and rising tone emissions, right-handed and nearly circularly polarized, and propagating away from the magnetic equator when they were observed at MMS (MLAT -31°). Most of the elements had "hook"-like signatures on their wave power spectra, characterized by enhanced wave power at flat or falling frequency following the peak, and all the elements exhibited complex and well-organized substructure observed consistently at all four MMS spacecraft at separations up to 70 km (60 km perpendicular and 38 km parallel to the background magnetic field). The waveforms in field-aligned coordinates also demonstrated that these waves were all phase coherent, allowing for the direct calculation of fi>k. Error estimates on calculated fi>k revealed that the plane wave approximation was valid for six of the eight elements and most of the subelements. The wave normal vectors were within 20-30° from the direction antiparallel to the background field for all elements and changed from subelement to subelement through at least two of the eight elements. The azimuthal angle of fi>k in the perpendicular plane was oriented earthward and was oblique to that of the Poynting vector, which has implications for the validity of cold plasma theory. (10.1002/2017JA024474)
DOI : 10.1002/2017JA024474
Vibrational excitation and temperature evolution in a pulsed CO2 discharge
- Guaitella Olivier
- Morillo-Candas Ana-Sofia
- Yap David
- Drag Cyril
- Booth Jean-Paul
- Klarenaar Bart
- Engeln Richard
- Grofulovic Marija
- Silva Tiago
- Guerra V.
, 2017, 62.
Simultaneous Diagnostic of Temperature Distribution and Electric Field induced in Dielectric Target by Atmospheric Pressure Plasma Jet
- Slikboer Elmar
- Garcia-Caurel Enric
- Sobota Ana
- Guaitella Olivier
, 2017, 62.
The I-mode confinement regime at ASDEX Upgrade: global properties and characterization of strongly intermittent density fluctuations
- Happel T.
- Manz P.
- Ryter F.
- Bernert M.
- Dunne M.
- Hennequin Pascale
- Hetzenecker A.
- Stroth U.
- Conway G. D.
- Guimarais L.
- Honoré Cyrille
- Viezzer E.
Plasma Physics and Controlled Fusion, IOP Publishing, 2017, 59 (1), pp.014004. Properties of the I-mode confinement regime on the ASDEX Upgrade tokamak are summarized. A weak dependence of the power threshold for the L-I transition on the toroidal magnetic field strength is found. During improved confinement, the edge radial electric field well deepens. Stability calculations show that the I-mode pedestal is peeling-ballooning stable. Turbulence investigations reveal strongly intermittent density fluctuations linked to the weakly coherent mode in the confined plasma, which become stronger as the confinement quality increases. Across all investigated structure sizes ( ##IMG## [http://ej.iop.org/images/0741-3335/59/1/014004/ppcfaa3b87ieqn001.gif] k_\bot≈ 5 ?12?cm ?1 , with ##IMG## [http://ej.iop.org/images/0741-3335/59/1/014004/ppcfaa3b87ieqn002.gif] k_\bot the perpendicular wavenumber of turbulent density fluctuations), the intermittent turbulence bursts are observed. Comparison with bolometry data shows that they move poloidally toward the X-point and finally end up in the divertor. This might be indicative that they play a role in inhibiting the density profile growth, such that no pedestal is formed in the edge density profile. (10.1088/0741-3335/59/1/014004)
DOI : 10.1088/0741-3335/59/1/014004
The 2017 Plasma Roadmap: Low temperature plasma science and technology
- Adamovich I.
- Baalrud S D
- Bogaerts A.
- Bruggeman P J
- Cappelli M.
- Colombo V.
- Czarnetzki U.
- Ebert U.
- Eden J G
- Favia P.
- Graves D B
- Hamaguchi S.
- Hieftje G.
- Hori M.
- Kaganovich I D
- Kortshagen U.
- Kushner M.J.
- Mason N J
- Mazouffre S.
- Mededovic Thagard S.
- Metelmann H-R
- Mizuno A.
- Moreau Éric
- Murphy a B
- Niemira B A
- Oehrlein G S
- Petrovic Z Lj
- Pitchford L C
- Pu Y-K
- Rauf S.
- Sakai O.
- Samukawa S.
- Starikovskaia Svetlana
- Tennyson J.
- Terashima K.
- Turner M.M.
- Sanden M C M van De
- Vardelle A.
Journal of Physics D: Applied Physics, IOP Publishing, 2017, 50 (32), pp.323001 (46 p.). Journal of Physics D: Applied Physics published the first Plasma Roadmap in 2012 consisting of the individual perspectives of 16 leading experts in the various sub-fields of low temperature plasma science and technology. The 2017 Plasma Roadmap is the first update of a planned series of periodic updates of the Plasma Roadmap. The continuously growing interdisciplinary nature of the low temperature plasma field and its equally broad range of applications are making it increasingly difficult to identify major challenges that encompass all of the many sub-fields and applications. This intellectual diversity is ultimately a strength of the field. The current state of the art for the 19 sub-fields addressed in this roadmap demonstrates the enviable track record of the low temperature plasma field in the development of plasmas as an enabling technology for a vast range of technologies that underpin our modern society. At the same time, the many important scientific and technological challenges shared in this roadmap show that the path forward is not only scientifically rich but has the potential to make wide and far reaching contributions to many societal challenges. (10.1088/1361-6463/aa76f5)
DOI : 10.1088/1361-6463/aa76f5
Overview of progress in European medium sized tokamaks towards an integrated plasma-edge/wall solution
- Meyer H.
- Eich T.
- Beurskens M.
- Coda S.
- Hakola A.
- Martin P.
- Adamek J.
- Agostini M.
- Aguiam D.
- Ahn J.
- Aho-Mantila L.
- Akers R.
- Albanese R.
- Aledda R.
- Alessi E.
- Allan S.
- Alves D.
- Ambrosino R.
- Amicucci L.
- Anand H.
- Anastassiou G.
- Andrèbe Y.
- Angioni C.
- Apruzzese G.
- Ariola M.
- Arnichand H.
- Arter W.
- Baciero A.
- Barnes M.
- Barrera Luis
- Behn R.
- Bencze A.
- Bernardo J.
- Bernert M.
- Bettini P.
- Bilková P.
- Bin W.
- Birkenmeier G.
- Bizarro J. P. S.
- Blanchard P.
- Blanken T.
- Bluteau M.
- Bobkov V.
- Bogar O.
- Böhm P.
- Bolzonella T.
- Boncagni L.
- Botrugno A.
- Bottereau C.
- Bouquey F.
- Bourdelle C.
- Brémond S.
- Brezinsek S.
- Brida D.
- Brochard F.
- Buchanan J.
- Bufferand H.
- Buratti P.
- Cahyna P.
- Calabrò G.
- Camenen Y.
- Caniello R.
- Cannas B.
- Canton A.
- Cardinali A.
- Carnevale D.
- Carr M.
- Carralero D.
- Carvalho P.
- Casali L.
- Castaldo C.
- Castejon F.
- Castro R.
- Causa F.
- Cavazzana R.
- Cavedon M.
- Cecconello M.
- Ceccuzzi S.
- Cesario R.
- Challis C. D.
- Chapman I. T.
- Chapman Scott C.
- Chernyshova M.
- Choi D.
- Cianfarani C.
- Ciraolo G.
- Citrin J.
- Clairet F.
- Classen I.
- Coelho R.
- Coenen J. W.
- Colas L.
- Conway G.
- Corre Y.
- Costea S.
- Crisanti F.
- Cruz N.
- Cseh G.
- Czarnecka A.
- d'Arcangelo O.
- de Angeli M.
- de Masi G.
- de Temmerman G.
- de Tommasi G.
- Decker J.
- Delogu R. S.
- Dendy R.
- Denner P.
- Di Troia C.
- Dimitrova M.
- d'Inca R.
- Doric V.
- Douai D.
- Drenik A.
- Dudson B.
- Dunai D.
- Dunne M.
- Duval B. P.
- Easy L.
- Elmore S.
- Erdös B.
- Esposito B.
- Fable E.
- Faitsch M.
- Fanni A.
- Fedorczak N.
- Felici F.
- Ferreira Jonathan
- Février O.
- Ficker O.
- Fietz S.
- Figini L.
- Figueiredo A.
- Fil A.
- Fishpool G.
- Fitzgerald M.
- Fontana M.
- Ford O.
- Frassinetti L.
- Fridström R.
- Frigione D.
- Fuchert G.
- Fuchs C.
- Furno Palumbo M.
- Futatani S.
- Gabellieri L.
- Galazka K.
- Galdon-Quiroga J.
- Galeani S.
- Gallart D.
- Gallo A.
- Galperti C.
- Gao Yu
- Garavaglia S.
- Garcia J.
- Garcia-Carrasco A.
- Garcia-Lopez J.
- Garcia-Munoz M.
- Gardarein J.-L.
- Garzotti L.
- Gaspar J.
- Gauthier E.
- Geelen P.
- Geiger B.
- Ghendrih P.
- Ghezzi F.
- Giacomelli L.
- Giannone L.
- Giovannozzi E.
- Giroud C.
- Gleason González C.
- Gobbin M.
- Goodman T. P.
- Gorini G.
- Gospodarczyk M.
- Granucci G.
- Gruber M.
- Gude A.
- Guimarais L.
- Guirlet R.
- Gunn J.
- Hacek P.
- Hacquin S.
- Hall S.
- Ham C.
- Happel T.
- Harrison J.
- Harting D.
- Hauer V.
- Havlícková E.
- Hellsten T.
- Helou W.
- Henderson S.
- Hennequin P.
- Heyn M.
- Hnat B.
- Hölzl M.
- Hogeweij D.
- Honoré C.
- Hopf C.
- Horácek J.
- Hornung G.
- Horváth L.
- Huang Z.
- Huber Armin
- Igitkhanov J.
- Igochine V.
- Imrisek M.
- Innocente P.
- Ionita-Schrittwieser C.
- Isliker H.
- Ivanova-Stanik I.
- Jacobsen A. S.
- Jacquet P.
- Jakubowski M.
- Jardin A.
- Jaulmes F.
- Jenko F.
- Jensen T.
- Jeppe Miki Busk O.
- Jessen M.
- Joffrin E.
- Jones O.
- Jonsson T.
- Kallenbach A.
- Kallinikos N.
- Kálvin S.
- Kappatou A.
- Karhunen J.
- Karpushov A.
- Kasilov S.
- Kasprowicz G.
- Kendl A.
- Kernbichler W.
- Kim D.
- Kirk A.
- Kjer S.
- Klimek I.
- Kocsis G.
- Kogut D.
- Komm M.
- Korsholm S. B.
- Koslowski H. R.
- Koubiti M.
- Kovacic J.
- Kovarik K.
- Krawczyk N.
- Krbec J.
- Krieger K.
- Krivska A.
- Kube R.
- Kudlacek O.
- Kurki-Suonio T.
- Labit B.
- Laggner F. M.
- Laguardia L.
- Lahtinen A.
- Lalousis P.
- Lang P.
- Lauber P.
- Lazányi N.
- Lazaros A.
- Le H. B.
- Lebschy A.
- Leddy J.
- Lefèvre Laure
- Lehnen M.
- Leipold F.
- Lessig A.
- Leyland M.
- Liang Yan-Chun
- Lipschultz B.
- Liu Y. Q.
- Loarer T.
- Loarte A.
- Loewenhoff T.
- Lomanowski B.
- Loschiavo V. P.
- Lunt T.
- Lupelli I.
- Lux H.
- Lyssoivan A.
- Madsen J.
- Maget P.
- Maggi C.
- Maggiora R.
- Magnussen M. L.
- Mailloux J.
- Maljaars B.
- Malygin A.
- Mantica P.
- Mantsinen M.
- Maraschek M.
- Marchand B.
- Marconato N.
- Marini C.
- Marinucci M.
- Markovic T.
- Marocco D.
- Marrelli L.
- Martin Y.
- Solis J. R. Martin
- Martitsch A.
- Mastrostefano S.
- Mattei M.
- Matthews G.
- Mavridis M.
- Mayoral M.-L.
- Mazon D.
- Mccarthy P.
- Mcadams R.
- Mcardle G.
- Mcclements K.
- Mcdermott R.
- Mcmillan B.
- Meisl G.
- Merle A.
- Meyer O.
- Milanesio D.
- Militello F.
- Miron I. G.
- Mitosinkova K.
- Mlynar J.
- Mlynek A.
- Molina D.
- Molina P.
- Monakhov I.
- Morales J.
- Moreau D.
- Morel Pierre
- Moret J.-M.
- Moro A.
- Moulton D.
- Müller H. W.
- Nabais F.
- Nardon E.
- Naulin V.
- Nemes-Czopf A.
- Nespoli F.
- Neu R.
- Nielsen A. H.
- Nielsen S. K.
- Nikolaeva V.
- Nimb S.
- Nocente M.
- Nouailletas R.
- Nowak S.
- Oberkofler M.
- Oberparleiter M.
- Ochoukov R.
- Odstrcil T.
- Olsen J.
- Omotani J.
- O'Mullane M. G.
- Orain F.
- Osterman N.
- Paccagnella R.
- Pamela S.
- Pangione L.
- Panjan M.
- Papp G.
- Paprok R.
- Parail V.
- Parra F. I.
- Pau A.
- Pautasso G.
- Pehkonen S.-P.
- Pereira A.
- Perelli Cippo E.
- Pericoli Ridolfini V.
- Peterka M.
- Petersson P.
- Petrzilka V.
- Piovesan P.
- Piron C.
- Pironti A.
- Pisano F.
- Pisokas T.
- Pitts R.
- Ploumistakis I.
- Plyusnin V.
- Pokol G.
- Poljak D.
- Pölöskei P.
- Popovic Z.
- Pór G.
- Porte L.
- Potzel S.
- Predebon I.
- Preynas M.
- Primc G.
- Pucella G.
- Puiatti M. E.
- Pütterich T.
- Rack M.
- Ramogida G.
- Rapson C.
- Rasmussen J. Juul
- Rattá G. A.
- Ratynskaia S.
- Ravera G.
- Réfy D.
- Reich M.
- Reimerdes H.
- Reimold F.
- Reinke M.
- Reiser D.
- Resnik M.
- Reux C.
- Ripamonti D.
- Rittich D.
- Riva G.
- Rodriguez-Ramos M.
- Rohde V.
- Rosato J.
- Ryter F.
- Saarelma S.
- Sabot R.
- Saint-Laurent F.
- Salewski M.
- Salmi A.
- Samaddar D.
- Sanchis-Sanchez L.
- Santos J.
- Sauter O.
- Scannell R.
- Scheffer M.
- Schneider M.
- Schneider B.
- Schneider P.
- Schneller M.
- Schrittwieser R.
- Schubert M.
- Schweinzer J.
- Seidl J.
- Sertoli M.
- Sesnic S.
- Shabbir A.
- Shalpegin A.
- Shanahan B.
- Sharapov S.
- Sheikh U.
- Sias G.
- Sieglin B.
- Silva C.
- Silva A.
- Silva Fuglister M.
- Simpson J.
- Snicker A.
- Sommariva C.
- Sozzi C.
- Spagnolo S.
- Spizzo G.
- Spolaore M.
- Stange T.
- Stejner Pedersen M.
- Stepanov I.
- Stober J.
- Strand P.
- Susnjara A.
- Suttrop W.
- Szepesi T.
- Tál B.
- Tala T.
- Tamain P.
- Tardini G.
- Tardocchi M.
- Teplukhina A.
- Terranova D.
- Testa D.
- Theiler C.
- Thornton A.
- Tolias P.
- Tophøj L.
- Treutterer W.
- Trevisan G. L.
- Tripsky M.
- Tsironis C.
- Tsui C.
- Tudisco O.
- Uccello A.
- Urban J.
- Valisa M.
- Vallejos P.
- Valovic M.
- van den Brand H.
- Vanovac B.
- Varoutis S.
- Vartanian S.
- Vega J.
- Verdoolaege G.
- Verhaegh K.
- Vermare L.
- Vianello N.
- Vicente J.
- Viezzer E.
- Vignitchouk L.
- Vijvers W. A. J.
- Villone F.
- Viola B.
- Vlahos L.
- Voitsekhovitch I.
- Vondrácek P.
- Vu N. M. T.
- Wagner D.
- Walkden N.
- Wang N.
- Wauters T.
- Weiland M.
- Weinzettl V.
- Westerhof E.
- Wiesenberger M.
- Willensdorfer M.
- Wischmeier M.
- Wodniak I.
- Wolfrum E.
- Yadykin D.
- Zagórski R.
- Zammuto I.
- Zanca P.
- Zaplotnik R.
- Zestanakis P.
- Zhang Wei
- Zoletnik S.
- Zuin M.
- Asdex Upgrade Team
- Mast Team
- Tcv Teams
Nuclear Fusion, IOP Publishing, 2017, 57. Integrating the plasma core performance with an edge and scrape-off layer (SOL) that leads to tolerable heat and particle loads on the wall is a major challenge. The new European medium size tokamak task force (EU-MST) coordinates research on ASDEX Upgrade (AUG), MAST and TCV. This multi-machine approach within EU-MST, covering a wide parameter range, is instrumental to progress in the field, as ITER and DEMO core/pedestal and SOL parameters are not achievable simultaneously in present day devices. A two prong approach is adopted. On the one hand, scenarios with tolerable transient heat and particle loads, including active edge localised mode (ELM) control are developed. On the other hand, divertor solutions including advanced magnetic configurations are studied. Considerable progress has been made on both approaches, in particular in the fields of: ELM control with resonant magnetic perturbations (RMP), small ELM regimes, detachment onset and control, as well as filamentary scrape-off-layer transport. For example full ELM suppression has now been achieved on AUG at low collisionality with n = 2 RMP maintaining good confinement {{H}\text{H (10.1088/1741-4326/aa6084)
DOI : 10.1088/1741-4326/aa6084
Multi-shell transport model for L-H transition
- Berionni Vincent
- Morel Pierre
- Gürcan Özgür D.
Physics of Plasmas, American Institute of Physics, 2017, 24 (12), pp.122310. A coupled model of transport, turbulence, and mesoscale flows is proposed, including turbulence spreading. The model consists of transport equations for plasma density and pressure coupled to a shell model of drift wave turbulence, which incorporates coupling to mesoscale flows via disparate scale interactions. The model can describe the turbulent cascade and its dynamical interplay with zonal and mean shear flows as well as the profile evolution (including the profiles of turbulence intensity itself) due to these self-consistent turbulent fluxes. This simple system of equations is shown to capture the low to high confinement (L-H) transition. It is also observed that as the heating is increased, the system goes through an intermediate phase that displays oscillations between zonal flows and turbulence. The transition towards the H mode, which is characterized by the presence of a strong mean shear flow at the edge, is triggered by the mesoscale dynamics due to the action of zonal flows, with turbulence spreading playing an important role in the H to L back transition. (10.1063/1.4998569)
DOI : 10.1063/1.4998569
Contribution à l'étude de la scintillation ionosphérique équatoriale sur la crête sud de l'Afrique
- Kahindo Bruno
- Kazadi Mukenga Bantu Albert
- Fleury Rolland
- Tondozi Keto Franck
- Zana Ndontoni André
- Kakule Kaniki Marc
- Amory-Mazaudier Christine
- Groves K.
Journal des sciences, Université Cheikh Anta Diop, 2017, 17 (2), pp.27-47. Cet article présente une étude sur la scintillation ionosphérique associée aux irrégularités équatoriales sur la crête sud de l'anomalie équatoriale. Les données utilisées sont le contenu électronique total (TEC) et l'indice de scintillation d'amplitude S4 enregistrées par le GPS SCINDA de Kinshasa (République Démocratique du Congo). Du fait de cette position géographique bien particulière, ces mesures constituent une opportunité de caractériser l'ionosphère sensible à de nombreux phénomènes spécifiques (forts gradients d'ionisation, scintillation, …). Le travail couvre la période qui va de mai 2011 à octobre 2012 situé dans la phase ascendante du cycle solaire numéro 24. Les résultats montrent que la scintillation est très intense avec des valeurs S4 voisines de 1 et au-delà pendant de nombreux jours de l'année. La répartition temporelle montre que les fortes valeurs de l'indice sont observées entre 19h à 23h TL (Temps Local). Ce résultat confirme que la scintillation est un phénomène présent dès le coucher du Soleil et peut se prolonger sur les quelques heures après minuit. On a aussi observé un fort effet saisonnier qui s'est manifesté par des valeurs intenses de scintillation aux mois d'équinoxe comparés aux périodes de solstice. Afin de mieux caractériser le degré d'ionisation dans la région équatoriale sud, nous avons utilisé les mesures GPS (pseudo-distances, bi-fréquences) effectuées par la station NKLG à Libreville au Gabon. C'est la seule station dans cette partie de l'Afrique qui possède une série historique de mesures sous forme de fichiers Rinex journaliers. Elle est rattachée au réseau IGS, ce qui garantit un suivi opérationnel très sérieux. Nous avons exploité ces mesures pour calculer le VTEC (Contenu Total Electronique vertical) et suivre le comportement de l'ionisation pendant la période de nos mesures. Le VTEC montre une variation diurne fonction de l'angle solaire zénithal (rayonnement solaire) et du rayonnement solaire ionisant. Ce dernier est quantifié par le nombre glissant de taches solaires (R12) permettant de situer notre période de mesures dans le cycle solaire en cours. Le VTEC est compris entre quelques unités d'unités de TEC (1 TECU=1016 el/m2) la nuit et 80-100 tecu de jour. Le maximum diurne est observé aux environs de 15 TL.
Concepts, Capabilities, and Limitations of Global Models: A Review
- Hurlbatt Andrew
- Gibson Andrew
- Schröter Sandra
- Bredin Jérôme
- Foote Alexander Paul Stuart
- Grondein Pascaline
- O'Connell D.
- Gans T.
Plasma Processes and Polymers, Wiley-VCH Verlag, 2017, 14 (1-2), pp.1600138. For researchers wishing to generate an understanding of complex plasma systems, global models often present an attractive first step, mainly due to their ease of development and use. These volume averaged models are able to give descriptions of plasmas with complex chemical kinetics, and without the computationally intensive numerical methods required for spatially resolved models. This paper gives a tutorial on global modeling, including development and techniques, and provides a discussion on the issues and pitfalls that researchers should be aware of. Further discussion is provided in the form of two reviews on methods of extending global modeling techniques to encompass variations in either time or space. (10.1002/ppap.201600138)
DOI : 10.1002/ppap.201600138
Transient propagation dynamics of flowing plasmas accelerated by radio-frequency electric fields
- Dedrick J.
- Gibson Andrew
- Rafalskyi D.V.
- Aanesland Ane
Physics of Plasmas, American Institute of Physics, 2017, 24, pp.050703. Flowing plasmas are of significant interest due to their role in astrophysical phenomena and potential applications in magnetic-confined fusion and spacecraft propulsion. The acceleration of a charge-neutral plasma beam using the radio-frequency self-bias concept could be particularly useful for the development of neutralizer-free propulsion sources. However, the mechanisms that lead to space-charge compensation of the exhaust beam are unclear. Here, we spatially and temporally resolve the propagation of electrons in an accelerated plasma beam that is generated using the self-bias concept with phase-resolved optical emission spectroscopy. When combined with measurements of the extraction-grid voltage, ion and electron currents, and plasma potential, the pulsed-periodic propagation of electrons during the interval of sheath collapse at the grids is found to enable the compensation of space charge. (10.1063/1.4983059)
DOI : 10.1063/1.4983059
Evidence for Quasi-adiabatic Motion of Charged Particles in Strong Current Sheets in the Solar Wind
- Malova H. V.
- Popov V. Y.
- Grigorenko E. E.
- Petrukovich A. A.
- Delcourt Dominique C.
- Sharma A. S.
- Khabarova O. V.
- Zelenyi L. M.
The Astrophysical Journal, American Astronomical Society, 2017, 834, pp.34. We investigate quasi-adiabatic dynamics of charged particles in strong current sheets (SCSs) in the solar wind, including the heliospheric current sheet (HCS), both theoretically and observationally. A self-consistent hybrid model of an SCS is developed in which ion dynamics is described at the quasi-adiabatic approximation, while the electrons are assumed to be magnetized, and their motion is described in the guiding center approximation. The model shows that the SCS profile is determined by the relative contribution of two currents: (i) the current supported by demagnetized protons that move along open quasi-adiabatic orbits, and (ii) the electron drift current. The simplest modeled SCS is found to be a multi-layered structure that consists of a thin current sheet embedded into a much thicker analog of a plasma sheet. This result is in good agreement with observations of SCSs at 1 au. The analysis of fine structure of different SCSs, including the HCS, shows that an SCS represents a narrow current layer (with a thickness of 104 km) embedded into a wider region of about 105 km, independently of the SCS origin. Therefore, multi-scale structuring is very likely an intrinsic feature of SCSs in the solar wind. (10.3847/1538-4357/834/1/34)
DOI : 10.3847/1538-4357/834/1/34
MMS Observations of Reconnection at Dayside Magnetopause Crossings During Transitions of the Solar Wind to Sub-Alfvénic Flow
- Farrugia C. J.
- Lugaz N.
- Alm L.
- Vasquez B.
- Argall M. R.
- Kucharek H.
- Matsui H.
- Torbert R. B.
- Lavraud B.
- Le Contel Olivier
- Cohen I. J.
- Burch J. L.
- Russell C. T.
- Strangeway R. J.
- Shuster J.
- Dorelli J. C.
- Eastwood Jonathan P.
- Ergun R. E.
- Fuselier S. A.
- Gershman D. J.
- Giles B. L.
- Khotyaintsev Y. V.
- Lindqvist P. A.
- Marklund G. T.
- Paulson K. W.
- Petrinec S. M.
- Phan T. D.
- Pollock C. J.
Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2017, 122 (10), pp.9934-9951. We present MMS observations during two dayside magnetopause crossings under hitherto unexamined conditions: (i) when the bow shock is weakening and the solar wind transitioning to sub-Alfvénic flow and (ii) when it is reforming. Interplanetary conditions consist of a magnetic cloud with (i) a strong B (20 nT) pointing south and (ii) a density profile with episodic decreases to values of 0.3 cm-3 followed by moderate recovery. During the crossings the magnetosheath magnetic field is stronger than the magnetosphere field by a factor of 2.2. As a result, during the outbound crossing through the ion diffusion region, MMS observed an inversion of the relative positions of the X and stagnation (S) lines from that typically the case: the S line was closer to the magnetosheath side. The S line appears in the form of a slow expansion fan near which most of the energy dissipation is taking place. While in the magnetosphere between the crossings, MMS observed strong field and flow perturbations, which we argue to be due to kinetic Alfvén waves. During the reconnection interval, whistler mode waves generated by an electron temperature anisotropy (Te⊥>Te||) were observed. Another aim of the paper is to distinguish bow shock-induced field and flow perturbations from reconnection-related signatures. The high-resolution MMS data together with 2-D hybrid simulations of bow shock dynamics helped us to distinguish between the two sources. We show examples of bow shock-related effects (such as heating) and reconnection effects such as accelerated flows satisfying the Walén relation. (10.1002/2017JA024563)
DOI : 10.1002/2017JA024563
Nanosecond surface dielectric barrier discharge in atmospheric pressure air: I. measurements and 2D modeling of morphology, propagation and hydrodynamic perturbations
- Zhu Yifei
- Shcherbanev S.A.
- Baron B.
- Starikovskaia Svetlana
Plasma Sources Science and Technology, IOP Publishing, 2017, 26 (12), pp.125004. A parallel 2D code for modeling nanosecond surface dielectric barrier discharge (nSDBD), combining a discharge description, detailed kinetics and hydrodynamics, is developed and validated. A series of experiments and numerical modeling for a single pulse nSDBD in atmospheric pressure air at a voltage amplitude of 24 kV have been performed. The measured and calculated velocity of the discharge front, electrical current, 2D map of N2 (\rmC^3\rmΠ _u)\to \rmN_2(\rmB^3\rmΠ _g) emission and hydrodynamic perturbations caused by the discharge on the time scale 0.2−5 μs are compared. The data are presented and analyzed for the negative and positive polarity of the streamers. A set of parametric calculations with different dielectric permittivities and different dielectric thicknesses is presented. (10.1088/1361-6595/aa9304)
DOI : 10.1088/1361-6595/aa9304
A model for tailored-waveform radiofrequency sheaths
- Chabert Pascal
- Turner Miles
Journal of Physics D: Applied Physics, IOP Publishing, 2017, 50 (23), pp.23LT02. The sheath physics of radiofrequency plasmas excited by a sinusoidal waveform is reasonably well understood, but the existing models are complicated and are not easily extended to the more complex waveforms recently introduced in applications. Turner and Chabert (2014 Appl. Phys. Lett . 104 164102) proposed a model for collisionless sheaths that can easily be solved for arbitrary waveforms. In this paper we extend this model to the case of collisional sheaths in the intermediate pressure regime. Analytical expressions are derived for the electric field, the electric potential and the density profiles in the sheath region. The collisionless and collisional models are compared for a pulsed-voltage waveform. (10.1088/1361-6463/aa6e42)
DOI : 10.1088/1361-6463/aa6e42
Controlled production of atomic oxygen and nitrogen in a pulsed radio-frequency atmospheric-pressure plasma
- Dedrick J.
- Schröter Sandra
- Niemi K.
- Wijaikhum A.
- Wagenaars E.
- Oliveira N De
- Nahon L.
- Booth Jean-Paul
- O'Connell D.
- Gans T.
Journal of Physics D: Applied Physics, IOP Publishing, 2017, 50 (45), pp.455204. Radio-frequency driven atmospheric pressure plasmas are efficient sources for the production of reactive species at ambient pressure and close to room temperature. Pulsing the radio-frequency power input provides additional control over species production and gas temperature. Here, we demonstrate the controlled production of highly reactive atomic oxygen and nitrogen in a pulsed radio-frequency ( ##IMG## [http://ej.iop.org/images/0022-3727/50/45/455204/daa8da2ieqn001.gif] 13.56 MHz) atmospheric-pressure plasma, operated with a small ##IMG## [http://ej.iop.org/images/0022-3727/50/45/455204/daa8da2ieqn002.gif] 0.1 % air-like admixture ( ##IMG## [http://ej.iop.org/images/0022-3727/50/45/455204/daa8da2ieqn003.gif] \rm N_2 / ##IMG## [http://ej.iop.org/images/0022-3727/50/45/455204/daa8da2ieqn004.gif] \rm O_2 at ##IMG## [http://ej.iop.org/images/0022-3727/50/45/455204/daa8da2ieqn005.gif] 4:1 ) through variations in the duty cycle. Absolute densities of atomic oxygen and nitrogen are determined through vacuum-ultraviolet absorption spectroscopy using the DESIRS beamline at the SOLEIL synchrotron coupled with a high resolution Fourier-transform spectrometer. The neutral-gas temperature is measured using nitrogen molecular optical emission spectroscopy. For a fixed applied-voltage amplitude (234?V), varying the pulse duty cycle from 10% to 100% at a fixed 10?kHz pulse frequency enables us to regulate the densities of atomic oxygen and nitrogen over the ranges of ##IMG## [http://ej.iop.org/images/0022-3727/50/45/455204/daa8da2ieqn006.gif] (0.18±0.03) ? ##IMG## [http://ej.iop.org/images/0022-3727/50/45/455204/daa8da2ieqn007.gif] (3.7±0.1)× 10^20 ##IMG## [http://ej.iop.org/images/0022-3727/50/45/455204/daa8da2ieqn008.gif] \rm m^-3 and ##IMG## [http://ej.iop.org/images/0022-3727/50/45/455204/daa8da2ieqn009.gif] (0.2±0.06) ? ##IMG## [http://ej.iop.org/images/0022-3727/50/45/455204/daa8da2ieqn010.gif] (4.4±0.8) × 10^19 ##IMG## [http://ej.iop.org/images/0022-3727/50/45/455204/daa8da2ieqn011.gif] \rm m^-3 , respectively. The corresponding 11?K increase in the neutral-gas temperature with increased duty cycle, up to a maximum of ##IMG## [http://ej.iop.org/images/0022-3727/50/45/455204/daa8da2ieqn012.gif] (314±4) K, is relatively small. This additional degree of control, achieved through regulation of the pulse duty cycle and time-averaged power, could be of particular interest for prospective biomedical applications. (10.1088/1361-6463/aa8da2)
DOI : 10.1088/1361-6463/aa8da2
Energy Cascade Rate in Compressible Fast and Slow Solar Wind Turbulence
- Hadid Lina
- Sahraoui Fouad
- Galtier Sébastien
The Astrophysical Journal, American Astronomical Society, 2017, 838 (1), pp.9. Estimation of the energy cascade rate in the inertial range of solar wind turbulence has been done so far mostly within incompressible magnetohydrodynamics (MHD) theory. Here, we go beyond that approximation to include plasma compressibility using a reduced form of a recently derived exact law for compressible, isothermal MHD turbulence. Using in situ data from the THEMIS/ARTEMIS spacecraft in the fast and slow solar wind, we investigate in detail the role of the compressible fluctuations in modifying the energy cascade rate with respect to the prediction of the incompressible MHD model. In particular, we found that the energy cascade rate (1) is amplified particularly in the slow solar wind; (2) exhibits weaker fluctuations in spatial scales, which leads to a broader inertial range than the previous reported ones; (3) has a power-law scaling with the turbulent Mach number; (4) has a lower level of spatial anisotropy. Other features of solar wind turbulence are discussed along with their comparison with previous studies that used incompressible or heuristic (nonexact) compressible MHD models. (10.3847/1538-4357/aa603f)
DOI : 10.3847/1538-4357/aa603f
Understanding of wavenumber spectra measured by Doppler reflectometry through simulation and related estimation of wave-plasma interaction regimes.
- Happel T.
- Görler T.
- Hennequin Pascale
- Lechte C.
- Pinzón J R
- Bernert M.
- Conway G. D.
- Freethy Simon
- Honoré Cyrille
- Stroth U.
- Asdex Upgrade Team The
, 2017.
Promoting lentil germination and stem growth by plasma activated tap water, demineralized water and liquid fertilizer
- Zhang Shiqiang
- Rousseau Antoine
- Dufour Thierry
RSC Advances, Royal Society of Chemistry, 2017, 7 (50), pp.31244–31251. Tap water, demineralized water and liquid fertilizer have been activated using an atmospheric pressure plasma jet (APPJ) to investigate their benefits for the germination rate and stem elongation rate of lentils from Puy-en-Velay (France). By plasma-activating tap water, we have obtained germination rates as high as 80% (instead of 30% with tap water). Also, higher stem elongation rates and final stem lengths were obtained using activated tap water compared with commercial fertilizer. We show that these rates of germination and stem growth strongly depend on the combination of two radicals generated in the liquids by the plasma: hydrogen peroxide and nitrate. This synergy appears to be a condition for releasing seed dormancy through the endogenous production of NO radicals. (10.1039/C7RA04663D)
DOI : 10.1039/C7RA04663D
Experimental study of the interaction of two laser-driven radiative shocks at the PALS laser
- Singh R. L.
- Stehlé C.
- Suzuki-Vidal F.
- Kozlova M.
- Larour Jean
- Chaulagain U.
- Clayson T.
- Rodriguez R.
- Gil M.
- Nejdl J.
- Krus M.
- Dostal J.
- Dudzak R.
- Barroso P.
- Acef O.
- Cotelo M.
- Velarde P.
High Energy Density Physics, Elsevier, 2017, 23, pp.20 - 30. Radiative shocks (RS) are complex phenomena which are ubiquitous in astrophysical environments. The study of such hypersonic shocks in the laboratory, under controlled conditions, is of primary interest to understand the physics at play and also to check the ability of numerical simulations to reproduce the experimental results. In this context, we conducted, at the Prague Asterix Laser System facility (PALS), the first experiments dedicated to the study of two counter-propagating radiative shocks propagating at non-equal speeds up to 25–50 km/s in noble gases at pressures ranging between 0.1 and 0.6 bar. These experiments highlighted the interaction between the two radiative precursors. This interaction is qualitatively but not quantitatively described by 1D simulations. Preliminary results obtained with XUV spectroscopy leading to the estimation of shock temperature and ion charge of the plasma are also presented. (10.1016/j.hedp.2017.03.001)
DOI : 10.1016/j.hedp.2017.03.001
Capacitively coupled hydrogen plasmas sustained by tailored voltage waveforms: vibrational kinetics and negative ions control
- Diomede P.
- Bruneau Bastien
- Longo S.
- Johnson E.V.
- Booth Jean-Paul
Plasma Sources Science and Technology, IOP Publishing, 2017, 26 (7), pp.075007. A comprehensive hybrid model of a hydrogen capacitively coupled plasma, including a detailed description of the molecular vibrational kinetics, has been applied to the study of the effect of tailored voltage waveforms (TVWs) on the production kinetics and transport of negative ions in these discharges. Two kinds of TVWs are considered, valleys-to-peaks and saw-tooth, with amplitude and slope asymmetry respectively. By tailoring the voltage waveform only, it is possible to exert substantial control over the peak density and position of negative ions inside the discharge volume. This control is particularly effective for saw-tooth waveforms. Insight into the mechanisms allowing this control is provided by an analysis of the model results. This reveals the roles of the vibrational distribution function and of the electron energy distribution and their correlations, as well as changes in the negative ion transport in the electric field when using different TVWs. Considering the chemical reactivity of H ? ions, the possibility of a purely electrical control of the negative ion cloud in a reactor operating with a feedstock gas diluted by hydrogen may find interesting applications. This is the first study of vibrational kinetics in the context of TVWs in molecular gases. (10.1088/1361-6595/aa752c)
DOI : 10.1088/1361-6595/aa752c
Three-dimensional Simulations and Spacecraft Observations of Sub-ion Scale Turbulence in the Solar Wind: Influence of Landau Damping
- Kobayashi Sumire
- Sahraoui Fouad
- Passot T.
- Laveder D.
- Sulem P.
- Huang S. Y.
- Henri Pierre
- Smets R.
The Astrophysical Journal, American Astronomical Society, 2017, 839 (2), pp.122. Three-dimensional nonlinear finite Larmor radius (FLR)–Landau fluid simulations, which include some small-scale $({k}_{\perp }{\rho }_{i}\gtrsim 1)$ kinetic effects, are performed to explore the nature of the sub-ion scale turbulence in the solar wind and to investigate the role of Landau damping and FLR corrections. The resulting steady-state magnetic power spectrum in the dispersive range display exponents that vary within a range of values compatible with statistical results reported from in situ spacecraft measurements of solar wind turbulence as well as from gyrokinetic simulations. The spectral slopes are shown to depend on the strength of the nonlinear effects and on the scale at which turbulent fluctuations are driven in the simulations. The influence of Landau damping is addressed by comparison with simulations where the double-adiabatic closure is imposed. The role of FLR corrections is also analyzed. Comparison with in situ observations in the solar wind are performed to enlighten the influence of the fluctuations power at different scales on the spectral slopes in the sub-ion range. Using diagnosis of both magnetic compressibility and frequency-wavenumber spectra, it is shown that in spite of the evidence of the presence of fast-magnetosonic modes, the magnetic energy is mostly distributed around the kinetic Alfvén waves and the slow modes, in agreement with solar wind measurements. The observed large broadening about the linear dispersion relations may reflect the presence of coherent structures. (10.3847/1538-4357/aa67f2)
DOI : 10.3847/1538-4357/aa67f2
Absolute ozone densities in a radio-frequency driven atmospheric pressure plasma using two-beam UV-LED absorption spectroscopy and numerical simulations
- Wijaikhum A.
- Schröder D.
- Schröter S.
- Gibson A. R.
- Niemi K.
- Friderich J.
- Greb A.
- Schulz-von der Gathen V.
- O'Connell D.
- Gans T.
Plasma Sources Science and Technology, IOP Publishing, 2017, 26. The efficient generation of reactive oxygen species (ROS) in cold atmospheric pressure plasma jets (APPJs) is an increasingly important topic, e.g. for the treatment of temperature sensitive biological samples in the field of plasma medicine. A 13.56 MHz radio-frequency (rf) driven APPJ device operated with helium feed gas and small admixtures of oxygen (up to 1%), generating a homogeneous glow-mode plasma at low gas temperatures, was investigated. Absolute densities of ozone, one of the most prominent ROS, were measured across the 11 mm wide discharge channel by means of broadband absorption spectroscopy using the Hartley band centred at lambda = 255 nm. A two-beam setup with a reference beam in Mach--Zehnder configuration is employed for improved signal-to-noise ratio allowing high-sensitivity measurements in the investigated single-pass weak-absorbance regime. The results are correlated to gas temperature measurements, deduced from the rotational temperature of the N2 (C 3 {{{\Pi }}}u \to B 3 {{{\Pi }}}g , upsilo = 0 \to 2) optical emission from introduced air impurities. The observed opposing trends of both quantities as a function of rf power input and oxygen admixture are analysed and explained in terms of a zero-dimensional plasma-chemical kinetics simulation. It is found that the gas temperature as well as the densities of O and O2(b{}1{{{Sigma }}}g ) influence the absolute O3 densities when the rf power is varied. (10.1088/1361-6595/aa8ebb)
DOI : 10.1088/1361-6595/aa8ebb
Vibrational kinetics of non-equilibrium CO2 plasma discharge in low-excitation regime
- Grofulovic Marija
- Silva Tiago
- Guerra V.
- Pintassilgo C.D.
- Klarenaar Bart
- Engeln Richard
- Morillo-Candas Ana-Sofia
- Guaitella Olivier
, 2017, 62.
Study of Plasma Waves Observed onboard Rosetta in the 67P/ChuryumovGerasimenko Comet Environment Using High Time Resolution Density Data Inferred from RPC-MIP and RPC-LAP Cross-calibration
- Breuillard H.
- Henri P.
- Vallières Xavier
- Eriksson A. I.
- Odelstad E.
- Johansson F. L.
- Richter I.
- Goetz C.
- Wattieaux G.
- Tsurutani B.
- Hajra R.
- Le Contel O.
, 2017, 2017. During two years, the groundbreaking ESA/Rosetta mission was able to escort comet 67P where previous cometary missions were only limited to flybys. This enabled for the first time to make in-situ measurements of the evolution of a comet's plasma environment. The density and temperature measured by Rosetta are derived from RPC-Mutual Impedance Probe (MIP) and RPC-Langmuir Probe (LAP). On one hand, low time resolution electron density are calculated using the plasma frequency extracted from the MIP mutual impedance spectra. On the other hand, high time resolution density fluctuations are estimated from the spacecraft potential measured by LAP. In this study, using a simple spacecraft charging model, we perform a cross-calibration of MIP plasma density and LAP spacecraft potential variations to obtain high time resolution measurements of the electron density. These results are also used to constrain the electron temperature. Then we make use of these new dataset, together with RPC-MAG magnetic field measurements, to investigate for the first time the compressibility and the correlations between plasma and magnetic field variations, for both singing comet waves and steepened waves observed, respectively during low and high cometary outgassing activity, in the plasma environment of comet 67P.

Retour aux années