Publications

2017

• Plasma sheath stability in the presence of secondary electrons emission
  
  • Martorelli Roberto
  • Croes Vivien
  • Tavant Antoine
  • Lucken Romain
  • Lafleur Trevor
  • Bourdon Anne
  • Chabert Pascal
  , 2017.
• Kinetic, Unstructured Finite Element PIC-DSMC Simulation of Ultra-Fast Pin-to-Plane Discharge in Air
  
  • Moore Christopher
  • Fierro Andrew
  • Pouvesle Jean-Michel
  • Robert Eric
  • Bourdon Anne
  • Jorgenson Roy
  • Jindal Ashish
  • Hopkins Mattew
  , 2017, 62 (10), pp.21. Recently, highly reproducible breakdown experiments in air at atmospheric pressure, leading to large volume homogeneous plasmas, have been performed in a 1.5 cm gap, pin-to-plane geometry with ˜2 ns rise-time [1]. The present work compares temporally resolved experimental results for the electric field and electron density to kinetic simulations using an unstructured finite element Particle-In-Cell code that models the collisions via Direct Simulation Monte Carlo. The model includes electronneutral elastic, excitation, ionization, and attachment collisions; ion and photon induced electron emission from surfaces; ion-neutral collisions; and self-absorption, photoionization, and photodissociation. The model tracks excited state neutrals which can be quenched through collisions with the background gas and surfaces or spontaneously emit a photon (isotropically) and transition to a lower state. [1] J-M. Pouvesle, et al. “Experimental Study of an Ultra-Fast Atmospheric Pressure Discharge in a Pin-to-Plate Geometry”, ICOPS 2017. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
• Kinetics of nanosecond discharges at high specific energy release
  
  • Starikovskaia Svetlana
  , 2017.
• Electric field rebound of He plasma jets with positive and negative polarities on metal and dielectric targets
  
  • Viegas Pedro
  • Obrusník A.
  • Bonaventura Z.
  • Bourdon Anne
  , 2017.
• Spectroscopic measurement of the electric field in a helium plasma jet - the influence of targets
  
  • Hofmans Marlous
  • Sobota Ana
  • Guaitella Olivier
  , 2018.
• Time evolution of vibrational temperatures in a CO 2 glow discharge measured with infrared absorption spectroscopy
  
  • Klarenaar M
  • Engeln R
  • van den Bekerom M
  • van de Sanden M. C. M.
  • Morillo-Candas A
  • Guaitella Olivier
  Plasma Sources Science and Technology, IOP Publishing, 2017, 26 (11). Vibrational temperatures of CO2 are studied in a pulsed glow discharge by means of time-resolvedin situ Fourier transform infrared spectroscopy, with a 10 μs temporal resolution. A method to analyzethe infrared transmittance through vibrationally excited CO2 is presented and validated on a previouslypublished CO2 spectrum, showing good agreement between fit and data. The discharge under study ispulsed with a typical duty cycle of 5–10 ms on–off, at 50 mA and 6.7 mbar. A rapid increase of thetemperature of the asymmetric stretch vibration (T3) is observed at the start of the pulse, reaching1050 K, which is an elevation of 550 K above the rotational temperature (Trot) of 500 K. After theplasma pulse, the characteristic relaxation time of T3 to Trot strongly depends on the rotationaltemperature. By adjusting the duty cycle, the rotational temperature directly after the discharge isvaried from 530 to 860 K, resulting in relaxation times between 0.4 and 0.1 ms. Equivalently, as thegas heats up during the plasma pulse, the elevation of T3 above Trot decreases strongly. (10.1088/1361-6595/aa902e)
  DOI : 10.1088/1361-6595/aa902e
• Coherent Structures at Ion Scales in Fast Solar Wind: Cluster Observations
  
  • Perrone D.
  • Alexandrova Olga
  • Roberts O.
  • Lion S.
  • Lacombe C.
  • Walsh A.
  • Maksimovic M.
  • Zouganelis I.
  The Astrophysical Journal, American Astronomical Society, 2017, 849 (1), pp.49. (10.3847/1538-4357/aa9022)
  DOI : 10.3847/1538-4357/aa9022
• Surface Mechanisms on Dielectric Surfaces Exposed to Low Pressure Glow Discharge and Atmospheric Pressure Plasma Jets
  
  • Guaitella Olivier
  • Morillo-Candas Ana-Sofia
  • Slikboer Elmar
  • Hofmans Marlous
  • Sobota Ana
  • Klarenaar Bart
  • Engeln Richard
  • Garcia-Caurel Enric
  • Guerra V.
  • Marinov Daniil
  , 2017.
• Modélisation numérique de la dynamique des ions froids dans le cadre de la reconnexion magnétique à la magnétopause terrestre
  
  • Dargent Jérémy
  , 2017. La reconnexion magnétique est un processus qui permet la conversion d'énergie magnétique en énergies cinétique et thermique, et autorise le mélange de plasmas. À la magnétopause terrestre, en particulier, elle est responsable d'un transfert d'énergie et de matière du vent solaire vers la magnétosphère. L'importance de ce transfert dépend du taux de reconnexion, qui lui-même varie en fonction des conditions locales du plasma. La présence fréquente à la magnétopause de populations froides d'origine ionosphérique est donc susceptible d'influer sur les propriétés et l'efficacité du processus. Cette thèse cherche à déterminer à l'aide de simulations numériques cinétiques quels sont les effets de ces populations froides sur la reconnexion magnétique asymétrique. La première partie de ce travail s'intéresse à la structure de la couche de courant et prouve, en se servant d'un équilibre cinétique récemment développé, que l'équilibre initial n'a en fait pas d'impact sur le développement de la reconnexion magnétique. Cette dernière ne dépend que du plasma reconnectant à un moment donné. Une deuxième partie de cette thèse montre que lorsque ce plasma contient des ions froids, ces derniers peuvent modifier des signatures observationelles des sites de reconnexion. La reconnexion magnétique chauffe et accélère également les ions froids. La troisième partie de ce travail prédit des signatures observationnelles inédites liées à cette dynamique et propose un modèle analytique pour expliquer l'une d'elles. Ces résultats pourront être confrontés aux données dans le cadre de la récente mission MMS, dont l'objectif est l'étude des sites de reconnexion à petite échelle.
• Modélisation bidimensionnelle de la décharge plasma dans un propulseur de Hall
  
  • Croes Vivien
  , 2017. Alors que les applications spatiales prennent une place de plus en plus cruciale dans nos vies, les coûts d'opération des satellites doivent être réduits. Ceci peut être obtenu par l'utilisation de systèmes de propulsion électriques, plus efficients que leurs homologues chimiques traditionnellement utilisés. Une des technologies de propulsion électrique la plus performante et la plus utilisée est le propulseur à effet Hall, toutefois ce système reste complexe et peu compris. En effet de nombreuses questions, concernant le transport anormal des électrons ou les interactions plasma/paroi, sont encore ouvertes.Les réponses à ces questions sont basées sur des mécanismes cinétiques et donc ne peuvent être résolues par des modèles fluides. De plus les caractéristiques géométriques et temporelles de ces mécanismes les rendent difficilement observables expérimentalement. Par conséquent nous avons, pour répondre à ces questions, développé un code cinétique bi-dimensionnel.Grâce à un modèle simplifié de propulseur à effet Hall, nous avons observé l'importance de l'instabilité de dérive électronique pour le transport anormal. Ensuite en utilisant un modèle réaliste de propulseur, nous avons pu étudier les effets des interactions plasma/paroi sur la décharge plasma. Nous avons également pu quantifier les effets intriqués des émissions électroniques secondaires et de l'instabilité de dérive sur le transport anormal. Par une étude paramétrique sur les émissions électroniques secondaires, nous avons pu identifier trois régimes de décharge plasma. Finalement l'impact des ergols alternatifs a pu être étudié en utilisant des processus collisionnels réalistes.
• Caractérisation d'un dispositif multijets plasma
  
  • Damany Xavier
  • Viegas Pedro
  • Bourdon Anne
  • Dozias Sébastien
  • Pouvesle Jean-Michel
  • Robert Eric
  , 2017.
• Global models of plasma thrusters: Insights from PIC simulation and fluid theory
  
  • Lucken Romain
  • Croes Vivien
  • Lafleur Trevor
  • Raimbault Jean-Luc
  • Bourdon Anne
  • Chabert Pascal
  , 2017. https://iepc2017.org/sites/default/files/speaker-papers/luckeniepc2017.pdf | PEGASES is an ion-ion thruster concept developed at LPP for over ten years. The neutralization of the plume by alternate negative and positive ion extraction leads to a thruster design where no external neutralizer is required anymore. First 0D fluid models - or global models - of plasma thrusters were developed for DC ion thrusters operated with Xenon. The model was extended to RF gridded thrusters including more complex molecular iodine chemistry. Recently, neutral gas heating by ion acceleration in the sheath was added to the model, which has a very large influence on the neutral power balance. Following the description of collisionless heating in inductively coupled RF plasma provided in [3], stochastic heating was also taken into account both through an effective collision frequency, and a heating term in the electron power balance. Refining the global model leads to a better predictability of the thruster efficiency. Both numerical PIC simulations and experiments are in progress to validate the analyses that were conducted here.
• Introduction à la Météorologie de l'Espace / Dynamos et Courants électriques Grande échelle
  
  • Amory-Mazaudier Christine
  , 2017. Soleil et Terre : 2 corps magnétiques en mouvement Emission du soleil Cycle solaire Dynamo solaire: le vrai cycle solaire/ indices solaires Le canal de la radiation régulière Ionosphère / Dynamo ionosphérique Le canal de la radiation perturbée Éruptions solaires solar flare Le canal des particules Vent solaire régulier Orages magnétiques CME (Ejection de matière coronale) et trous coronaux Activité magnétique et Activité solaire Dynamo ionosphérique et Dynamo terrestre Les courants électriques associés aux différentes dynamos LIonosphère équatoriale Conclusion
• Kinetics of Metastable Molecules and O atoms in O<SUB>2</SUB> Plasmas
  
  • Chatterjee Abhyuday
  • Booth Jean-Paul
  • Guaitella Olivier
  • Morillo-Candas Ana-Sofia
  • Drag Cyril
  • Nahon L.
  • de Oliveira N.
  • Zyryanov Sergey
  • Lopaev Dmitry
  , 2017.
• Study of electron transport in a Hall effect thruster with 2D (r-theta) Particle-In-Cell simulations
  
  • Croes Vivien
  • Tavant Antoine
  • Lucken Romain
  • Lafleur Trevor
  • Bourdon Anne
  • Chabert Pascal
  , 2017. https://iepc2017.org/sites/default/files/speaker-papers/study-electron-transport.pdf
• Phase-resolved optical emission spectroscopy of a neutralizer-free gridded ion thruster
  
  • Dedrick J.
  • Gibson Andrew
  • Rafalskyi D.V.
  • Aanesland Ane
  , 2017.
• A Neutralizer-Free Gridded Ion Thruster Embedded Into A 1U Cubesat Module
  
  • Rafalskyi D.V.
  • Aanesland Ane
  , 2017.
• Overview of the TCV tokamak program: scientific progress and facility upgrades
  
  • Coda S.
  • Ahn J.
  • Albanese R.
  • Alberti S.
  • Alessi E.
  • Allan S.
  • Anand H.
  • Anastassiou G.
  • Andrebe Y.
  • Angioni C.
  • Ariola M.
  • Bernert M.
  • Beurskens M.
  • Bin W.
  • Blanchard P.
  • Blanken T. C.
  • Boedo J. A.
  • Bolzonella T.
  • Bouquey F.
  • Braunmueller F. H.
  • Bufferand H.
  • Buratti P.
  • Calabro G.
  • Camenen Y.
  • Carnevale D.
  • Carpanese F.
  • Causa F.
  • Cesario R.
  • Chapman I. T.
  • Chellai O.
  • Choi D.
  • Cianfarani C.
  • Ciraolo G.
  • Citrin J.
  • Costea S.
  • Crisanti F.
  • Cruz N.
  • Czarnecka A.
  • Decker J.
  • de Masi G.
  • de Tommasi G.
  • Douai D.
  • Dunne M.
  • Duval B. P.
  • Eich T.
  • Elmore S.
  • Esposito B.
  • Faitsch M.
  • Fasoli A.
  • Fedorczak N.
  • Felici F.
  • Fevrier O.
  • Ficker O.
  • Fietz S.
  • Fontana M.
  • Frassinetti L.
  • Furno I.
  • Galeani S.
  • Gallo A.
  • Galperti C.
  • Garavaglia S.
  • Garrido I.
  • Geiger B.
  • Giovannozzi E.
  • Gobbin M.
  • Goodman T. P.
  • Gorini G.
  • Gospodarczyk M.
  • Granucci G.
  • Graves J. P.
  • Guirlet R.
  • Hakola A.
  • Ham C.
  • Harrison J.
  • Hawke J.
  • Hennequin P.
  • Hnat B.
  • Hogeweij D.
  • Hogge J. -Ph.
  • Honore C.
  • Hopf C.
  • Horacek J.
  • Huang Z.
  • Igochine V.
  • Innocente P.
  • Schrittwieser C. Ionita
  • Isliker H.
  • Jacquier R.
  • Jardin A.
  • Kamleitner J.
  • Karpushov A.
  • Keeling D. L.
  • Kirneva N.
  • Kong M.
  • Koubiti M.
  • Kovacic J.
  • Kramer-Flecken A.
  • Krawczyk N.
  • Kudlacek O.
  • Labit B.
  • Lazzaro E.
  • Le H. B.
  • Lipschultz B.
  • Llobet X.
  • Lomanowski B.
  • Loschiavo V. P.
  • Lunt T.
  • Maget P.
  • Maljaars E.
  • Malygin A.
  • Maraschek M.
  • Marini C.
  • Martin P.
  • Martin Y.
  • Mastrostefano S.
  • Maurizio R.
  • Mavridis M.
  • Mazon D.
  • Mcadams R.
  • Mcdermott R.
  • Merle A.
  • Meyer H.
  • Militello F.
  • Miron I. G.
  • Cabrera P. A. Molina
  • Moret J. -M.
  • Moro A.
  • Moulton D.
  • Naulin V.
  • Nespoli F.
  • Nielsen A. H.
  • Nocente M.
  • Nouailletas R.
  • Nowak S.
  • Odstrcil T.
  • Papp G.
  • Paprok R.
  • Pau A.
  • Pautasso G.
  • Ridolfini V. Pericoli
  • Piovesan P.
  • Piron C.
  • Pisokas T.
  • Porte L.
  • Preynas M.
  • Ramogida G.
  • Rapson C.
  • Rasmussen J. Juul
  • Reich M.
  • Reimerdes H.
  • Reux C.
  • Ricci P.
  • Rittich D.
  • Riva F.
  • Robinson T.
  • Saarelma S.
  • Saint-Laurent F.
  • Sauter O.
  • Scannell R.
  • Schlatter Ch.
  • Schneider B.
  • Schneider P.
  • Schrittwieser R.
  • Sciortino F.
  • Sertoli M.
  • Sheikh U.
  • Sieglin B.
  • Silva M.
  • Sinha J.
  • Sozzi C.
  • Spolaore M.
  • Stange T.
  • Stoltzfus-Dueck T.
  • Tamain P.
  • Teplukhina A.
  • Testa D.
  • Theiler C.
  • Thornton A.
  • Tophoj L.
  • Tran M. Q.
  • Tsironis C.
  • Tsui C.
  • Uccello A.
  • Vartanian S.
  • Verdoolaege G.
  • Verhaegh K.
  • Vermare L.
  • Vianello N.
  • Vijvers W. A. J.
  • Vlahos L.
  • Vu N. M. T.
  • Walkden N.
  • Wauters T.
  • Weisen H.
  • Wischmeier M.
  • Zestanakis P.
  • Zuin M.
  • 1team Eurofusion Mst
  Nuclear Fusion, IOP Publishing, 2017, 57 (10). The TCV tokamak is augmenting its unique historical capabilities (strong shaping, strong electron heating) with ion heating, additional electron heating compatible with high densities, and variable divertor geometry, in a multifaceted upgrade program designed to broaden its operational range without sacrificing its fundamental flexibility. The TCV program is rooted in a three-pronged approach aimed at ITER support, explorations towards DEMO, and fundamental research. A 1 MW, tangential neutral beam injector (NBI) was recently installed and promptly extended the TCV parameter range, with record ion temperatures and toroidal rotation velocities and measurable neutral-beam current drive. ITER-relevant scenario development has received particular attention, with strategies aimed at maximizing performance through optimized discharge trajectories to avoid MHD instabilities, such as peeling-ballooning and neoclassical tearing modes. Experiments on exhaust physics have focused particularly on detachment, a necessary step to a DEMO reactor, in a comprehensive set of conventional and advanced divertor concepts. The specific theoretical prediction of an enhanced radiation region between the two X-points in the low-field-side snowflake-minus configuration was experimentally confirmed. Fundamental investigations of the power decay length in the scrape-off layer (SOL) are progressing rapidly, again in widely varying configurations and in both D and He plasmas; in particular, the double decay length in L-mode limited plasmas was found to be replaced by a single length at high SOL resistivity. Experiments on disruption mitigation by massive gas injection and electron-cyclotron resonance heating (ECRH) have begun in earnest, in parallel with studies of runaway electron generation and control, in both stable and disruptive conditions; a quiescent runaway beam carrying the entire electrical current appears to develop in some cases. Developments in plasma control have benefited from progress in individual controller design and have evolved steadily towards controller integration, mostly within an environment supervised by a tokamak profile control simulator. TCV has demonstrated effective wall conditioning with ECRH in He in support of the preparations for JT-60SA operation. (10.1088/1741-4326/aa6412)
  DOI : 10.1088/1741-4326/aa6412
• Overview of ASDEX Upgrade results
  
  • Kallenbach A.
  • Aguiam D.
  • Aho-Mantila L.
  • Angioni C.
  • Arden N.
  • Parra R. Arredondo
  • Asunta O.
  • Baar M. De
  • Balden M.
  • Behler K.
  • Bergmann A.
  • Bernardo J.
  • Bernert M.
  • Beurskens M.
  • Biancalani A.
  • Bilato R.
  • Birkenmeier G.
  • Bobkov V.
  • Bock A.
  • Bogomolov A.
  • Bolzonella T.
  • Boswirth B.
  • Bottereau C.
  • Bottino A.
  • Brand H. van Den
  • Brezinsek S.
  • Brida D.
  • Brochard F.
  • Bruhn C.
  • Buchanan J.
  • Buhler A.
  • Burckhart A.
  • Cambon-Silva D.
  • Camenen Y.
  • Carvalho P.
  • Carrasco G.
  • Cazzaniga C.
  • Carr M.
  • Carralero D.
  • Casali L.
  • Castaldo C.
  • Cavedon M.
  • Challis C.
  • Chankin A.
  • Chapman I.
  • Clairet F.
  • Classen I.
  • Coda S.
  • Coelho R.
  • Coenen J. W.
  • Colas L.
  • Conway G.
  • Costea S.
  • Coster D. P.
  • Croci G.
  • Cseh G.
  • Czarnecka A.
  • d'Arcangelo O.
  • Day C.
  • Delogu R.
  • Marne P. De
  • Denk S.
  • Denner P.
  • Dibon M.
  • d'Inca R.
  • Di Siena A.
  • Douai D.
  • Drenik A.
  • Drube R.
  • Dunne M.
  • Duval B. P.
  • Dux R.
  • Eich T.
  • Elgeti S.
  • Engelhardt K.
  • Erdos B.
  • Erofeev I.
  • Esposito B.
  • Fable E.
  • Faitsch M.
  • Fantz U.
  • Faugel H.
  • Felici F.
  • Fietz S.
  • Figueredo A.
  • Fischer R.
  • Ford O.
  • Frassinetti L.
  • Freethy S.
  • Froschle M.
  • Fuchert G.
  • Fuchs J. C.
  • Funfgelder H.
  • Galazka K.
  • Galdon-Quiroga J.
  • Gallo A.
  • Gao Y.
  • Garavaglia S.
  • Garcia-Munoz M.
  • Geiger B.
  • Cianfarani C.
  • Giannone L.
  • Giovannozzi E.
  • Gleason-Gonzalez C.
  • Gloggler S.
  • Gobbin M.
  • Gorler T.
  • Goodman T.
  • Gorini G.
  • Gradic D.
  • Grater A.
  • Granucci G.
  • Greuner H.
  • Griener M.
  • Groth M.
  • Gude A.
  • Gunter S.
  • Guimarais L.
  • Haas G.
  • Hakola A. H.
  • Ham C.
  • Happel T.
  • Harrison J.
  • Hatch D.
  • Hauer V.
  • Hayward T.
  • Heinemann B.
  • Heinzel S.
  • Hellsten T.
  • Henderson S.
  • Hennequin P.
  • Herrmann A.
  • Heyn E.
  • Hitzler F.
  • Hobirk J.
  • Holzl M.
  • Hoschen T.
  • Holm J. H.
  • Hopf C.
  • Hoppe F.
  • Horvath L.
  • Houben A.
  • Huber A.
  • Igochine V.
  • Ilkei T.
  • Ivanova-Stanik I.
  • Jacob W.
  • Jacobsen A. S.
  • Jacquot J.
  • Janky F.
  • Jardin A.
  • Jaulmes F.
  • Jenko F.
  • Jensen T.
  • Joffrin E.
  • Kasemann C.
  • Kalvin S.
  • Kantor M.
  • Kappatou A.
  • Kardaun O.
  • Karhunen J.
  • Kasilov S.
  • Kernbichler W.
  • Kim D.
  • Kimmig S.
  • Kirk A.
  • Klingshirn H. -J.
  • Koch F.
  • Kocsis G.
  • Kohn A.
  • Kraus M.
  • Krieger K.
  • Krivska A.
  • Kramer-Flecken A.
  • Kurki-Suonio T.
  • Kurzan B.
  • Lackner K.
  • Laggner F.
  • Lang P. T.
  • Lauber P.
  • Lazanyi N.
  • Lazaros A.
  • Lebschy A.
  • Li L.
  • Li M.
  • Liang Y.
  • Lipschultz B.
  • Liu Y.
  • Lohs A.
  • Luhmann N. C.
  • Lunt T.
  • Lyssoivan A.
  • Madsen J.
  • Maier H.
  • Maj O.
  • Mailloux J.
  • Maljaars E.
  • Manas P.
  • Mancini A.
  • Manhard A.
  • Manso M. -E.
  • Mantica P.
  • Mantsinen M.
  • Manz P.
  • Maraschek M.
  • Martens C.
  • Martin P.
  • Marrelli L.
  • Martitsch A.
  • Mastrostefano S.
  • Mayer A.
  • Mayer M.
  • Mazon D.
  • Mccarthy P. J.
  • Mcdermott R.
  • Meisl G.
  • Meister H.
  • Medvedeva A.
  • Merkel P.
  • Merkel R.
  • Merle A.
  • Mertens V.
  • Meshcheriakov D.
  • Meyer H.
  • Meyer O.
  • Miettunen J.
  • Milanesio D.
  • Mink F.
  • Mlynek A.
  • Monaco F.
  • Moon C.
  • Nazikian R.
  • Nemes-Czopf A.
  • Neu G.
  • Neu R.
  • Nielsen A. H.
  • Nielsen S. K.
  • Nikolaeva V.
  • Nocente M.
  • Noterdaeme J. -M.
  • Nowak S.
  • Oberkofler M.
  • Oberparleiter M.
  • Ochoukov R.
  • Odstrcil T.
  • Olsen J.
  • Orain F.
  • Palermo F.
  • Papp G.
  • Perez I. Paradela
  • Pautasso G.
  • Enzel F.
  • Petersson P.
  • Pinzon J.
  • Piovesan P.
  • Piron C.
  • Plaum B.
  • Plockl B.
  • Plyusnin V.
  • Pokol G.
  • Poli E.
  • Porte L.
  • Potzel S.
  • Prisiazhniuk D.
  • Putterich T.
  • Ramisch M.
  • Rapson C.
  • Rasmussen J.
  • Raupp G.
  • Refy D.
  • Reich M.
  • Reimold F.
  • Ribeiro T.
  • Riedl R.
  • Rittich D.
  • Rocchi G.
  • Rodriguez-Ramos M.
  • Rohde V.
  • Ross A.
  • Rott M.
  • Rubel M.
  • Ryan D.
  • Ryter F.
  • Saarelma S.
  • Salewski M.
  • Salmi A.
  • Sanchis-Sanchez L.
  • Santos G.
  • Santos J.
  • Sauter O.
  • Scarabosio A.
  • Schall G.
  • Schmid K.
  • Schmitz O.
  • Schneider P. A.
  • Schneller M.
  • Schrittwieser R.
  • Schubert M.
  • Schwarz-Selinger T.
  • Schweinzer J.
  • Scott B.
  • Sehmer T.
  • Sertoli M.
  • Shabbir A.
  • Shalpegin A.
  • Shao L.
  • Sharapov S.
  • Siccinio M.
  • Sieglin B.
  • Sigalov A.
  • Silva A.
  • Silva C.
  • Simon P.
  • Simpson J.
  • Snicker A.
  • Sommariva C.
  • Sozzi C.
  • Spolaore M.
  • Stejner M.
  • Stober J.
  • Stobbe F.
  • Stroth U.
  • Strumberger E.
  • Suarez G.
  • Sugiyama K.
  • Sun H. -J.
  • Suttrop W.
  • Szepesi T.
  • Tal B.
  • Tala T.
  • Tardini G.
  • Tardocchi M.
  • Terranova D.
  • Tierens W.
  • Told D.
  • Tudisco O.
  • Trevisan G.
  • Treutterer W.
  • Trier E.
  • Tripsky M.
  • Valisa M.
  • Valovic M.
  • Vanovac B.
  • Varela P.
  • Varoutis S.
  • Verdoolaege G.
  • Vezinet D.
  • Vianello N.
  • Vicente J.
  • Vierle T.
  • Viezzer E.
  • Toussaint U. Von
  • Wagner D.
  • Wang N.
  • Wang X.
  • Weidl M.
  • Weiland M.
  • White A. E.
  • Willensdorfer M.
  • Wiringer B.
  • Wischmeier M.
  • Wolf R.
  • Wolfrum E.
  • Xiang L.
  • Yang Q.
  • Yang Z.
  • Yu Q.
  • Zagorski R.
  • Zammuto I.
  • Zarzoso D.
  • Zhang W.
  • Zeeland M. Van
  • Zehetbauer T.
  • Zilker M.
  • Zoletnik S.
  • Zohm H.
  • Team Asdex Upgrade
  • Team Eurofusion Mst1
  Nuclear Fusion, IOP Publishing, 2017, 57 (10). The ASDEX Upgrade (AUG) programme is directed towards physics input to critical elements of the ITER design and the preparation of ITER operation, as well as addressing physics issues for a future DEMO design. Since 2015, AUG is equipped with a new pair of 3-strap ICRF antennas, which were designed for a reduction of tungsten release during ICRF operation. As predicted, a factor two reduction on the ICRF-induced W plasma content could be achieved by the reduction of the sheath voltage at the antenna limiters via the compensation of the image currents of the central and side straps in the antenna frame. There are two main operational scenario lines in AUG. Experiments with low collisionality, which comprise current drive, ELM mitigation/suppression and fast ion physics, are mainly done with freshly boronized walls to reduce the tungsten influx at these high edge temperature conditions. Full ELM suppression and non-inductive operation up to a plasma current of I-p = 0.8 MA could be obtained at low plasma density. Plasma exhaust is studied under conditions of high neutral divertor pressure and separatrix electron density, where a fresh boronization is not required. Substantial progress could be achieved for the understanding of the confinement degradation by strong D puffing and the improvement with nitrogen or carbon seeding. Inward/outward shifts of the electron density profile relative to the temperature profile effect the edge stability via the pressure profile changes and lead to improved/decreased pedestal performance. Seeding and D gas puffing are found to effect the core fueling via changes in a region of high density on the high field side (HFSHD). The integration of all above mentioned operational scenarios will be feasible and naturally obtained in a large device where the edge is more opaque for neutrals and higher plasma temperatures provide a lower collisionality. The combination of exhaust control with pellet fueling has been successfully demonstrated. High divertor enrichment values of nitrogen E-N >= 10 have been obtained during pellet injection, which is a prerequisite for the simultaneous achievement of good core plasma purity and high divertor radiation levels. Impurity accumulation observed in the all-metal AUG device caused by the strong neoclassical inward transport of tungsten in the pedestal is expected to be relieved by the higher neoclassical temperature screening in larger devices. (10.1088/1741-4326/aa64f6)
  DOI : 10.1088/1741-4326/aa64f6
• Effects of collisions on the magnetic streaming instability
  
  • Nicolas Loïc
  , 2017. When a beam of energetic ions streams in a magnetized plasma background with a bulk velocity higher than the local Alfvén speed, it can drive electromagnetic waves unstable. The result is enhanced magnetic field fluctuations, the slowing down of the beam and plasma heating. This so-called magnetic streaming instability is commonly present in space plasma, such as streaming cosmic rays in the interstellar medium or reflected ions at shocks, as well as in laboratory plasmas. Under certain physical conditions, Coulomb collisions between ions can influence and even suppress the development of the instability. This work provides the first investigation of such effects. We study the magnetic streaming instability numerically with a hybrid-PIC code with a newly developed Monte Carlo ion-ion Coulomb collision module. Our results for the collisionless regime confirm previous studies related to the existence of resonant and non-resonant modes, and provide the groundwork for the comparison with the collisional cases. We find that collisions generally lower the amplitude of the magnetic field fluctuations, and we identify several regimes which are characterized by the competition between the growth of the instability and collisions. Even in weakly-collisional plasmas, the slowing down of the beam can actually induce a rapid increase of collisional energy exchanges, which leave less free energy for the non-linear growth of the magnetic field fluctuations and cause a more efficient heating of the plasma. For the resonant mode the enhanced heating of the beam reduces the number of particles resonating with the waves and leads to a reduction of its growth rate.
• High resolution Two-photon Absorption Laser-Induced Fluorescence (TALIF) with a single-mode nanosecond Ti:Sapphire laser
  
  • Morillo-Candas Ana-Sofia
  • Lottigier Pierre
  • Drag Cyril
  • Blondel Christophe
  • Booth Jean-Paul
  • Guaitella Olivier
  , 2017.
• Iodine atom detection in a plasma thruster by infrared diode laser absorption
  
  • Booth Jean-Paul
  • Courtois Theo
  , 2017.
• Spatiotemporally resolved rotational Raman spectroscopy in a pulsed CO<SUB>2</SUB> glow discharge
  
  • Klarenaar Bart
  • Bekerom D C M van Den
  • Damen Mark
  • Grofulovic Marija
  • Guaitella Olivier
  • Morillo-Candas Ana-Sofia
  • Sanden M C M van De
  • Engeln Richard
  , 2017.
• The role of translational and vibrational energy in processing plasmas: novel optical diagnostics of low-pressure Cl<SUB>2</SUB> and O<SUB>2</SUB> inductively-coupled plasmas
  
  • Booth Jean-Paul
  , 2017.
• Laser-driven radiative shock waves and their characterization using interferometry and spectroscopy
  
  • Singh Raj Laxmi
  , 2017.