Publications

2013

• RF measurements in the ferrite-enhanced PEGASES II space thruster prototype : power efficiency and range of operation
  
  • Rafalskyi D.V.
  • Aanesland Ane
  • Bredin Jérôme
  • Chabert Pascal
  , 2013.
• Inductively-coupled plasmas in pure chlorine: comparison of atom density, electron density and gas temperature measurements with the HPEM hybrid model.
  
  • Booth Jean-Paul
  • Sirse Nishant
  • Chabert Pascal
  • Pruvost B.
  • Kushner M.J.
  , 2013.
• Status on the Project of Laser Based Production, Acceleration and Neutralization of High Power Neutral (H or D) Beam for Demo Application
  
  • Moustaizis Stavros
  • Auvray Philippe
  • Larour Jean
  • Perrakis C.
  • Ducret J.-E.
  , 2013. communication orale
• Origin of extracted H- ions at different plasma grid bias in caesiated ion sources
  
  • Bacal M.
  • Mcadams R.
  • Surrey E.
  , 2013.
• Generation of High Pulsed magnetic field using low inductance switches
  
  • Auvray Philippe
  • Larour Jean
  • Moustaizis Stavros
  , 2013. On présente plusieurs dispositifs de production de courants intenses (jusqu'à 900 kA sous 30 kV) pour magnétiser des volumes d'interaction laser-matière de quelques cm3 pendant environ 1 µs. L'accent est mis sur la réalisation de deux types d'éclateur à très faible inductance et sur la connexion à une chambre à vide.
• Numerical Evaluation of the Role of Reflectors to Maximize the Power Efficiency of an Axial Vircator (keynote)
  
  • Champeaux Stéphanie
  • Gouard Philippe
  • Cousin Richard
  • Larour Jean
  , 2013, pp.4A-High Power Microwaves I. Keynote speech on HPM. The effects of introducing one or more reflectors inside an axial Vircator are analyzed using CST-Particle Studio (TM) PIC simulation. The power conversion efficiency is shown to be enhanced from 1% to 13% at 3 GHz. The optimum output power is obtained with three reflectors. Abstract disponible sur http://www.ivec2013.org/ Texte de 2 pages sur clé USB distribué aux participants mais non public.
• Propagation of Plasmas in Liquids
  
  • Rousseau Antoine
  , 2013.
• Guiding of meter scale AC discharges by laser filamentation in air
  
  • Houard Aurélien
  • Brelet Yohann
  • Point G.
  • Carbonnel Jérôme
  • André Y-B.
  • Prade Bernard S.
  • Arantchouk Léonid
  • Mysyrowicz André
  , 2013. We report experiments of laser-guided discharges obtained in air with high voltage bursts delivered by a compact Tesla coil. Characteristics of the guided discharges are studied for electrode gaps ranging from 30 to 170 cm.
• Plasma column from laser filamentation in air as a virtual radio-frequency antenna
  
  • Point G.
  • Brelet Yohann
  • Houard Aurélien
  • Carbonnel Jérôme
  • Arantchouk Léonid
  • Prade Bernard S.
  • André Y-B.
  • Mysyrowicz André
  , 2013. We demonstrate the use of a plasma column created by femtosecond filamentation and heated by means of a high-voltage discharge communication orale CD-10.1
• Dynamics of Cl<SUB>2</SUB> inductively-coupled plasmas: Role of electronic and vibrational excitation
  
  • Booth Jean-Paul
  • Sirse Nishant
  • Chabert Pascal
  • Indelicato P.
  • Surzhykov A.
  • Kushner M.J.
  , 2013.
• Development of plasma and beam diagnostics for the PEGASES thruster experiment
  
  • Rafalskyi D.V.
  • Aanesland Ane
  , 2013.
• A simple high-voltage high current spark gap with subnanosecond jitter triggered by femtosecond laser filamentation
  
  • Arantchouk Léonid
  • Houard Aurélien
  • Brelet Yohann
  • Carbonnel Jérôme
  • Larour Jean
  • André Yves-Bernard
  • Mysyrowicz André
  Applied Physics Letters, American Institute of Physics, 2013, 102 (16), pp.162502. We describe a simple, sturdy, and reliable spark gap operating with air at atmospheric pressure and able to switch currents in excess of 10 kA with sub-nanosecond jitter. The spark gap is remotely triggered by a femtosecond laser filament. (10.1063/1.4802927)
  DOI : 10.1063/1.4802927
• The optimized steerable W-band Doppler reflectometer on ASDEX Upgrade: possibilities and issues
  
  • Happel T.
  • Conway G. D.
  • Hennequin Pascale
  • Honoré Cyrille
  • Giacalone J-C.
  • Simon P.
  • Stroth U.
  • Vermare Laure
  • Asdex Upgrade Team The
  , 2013 (http://www.lptp.polytechnique.fr/News/11/Workshop/papers/Happel_IRW11-paper.pdf).
• Doppler backscattering measurements on TCV
  
  • Vermare Laure
  • Coda S.
  • Hennequin Pascale
  • de Meijere K.
  • Honoré Cyrille
  • Giacalone J-C.
  • Tcv Team
  , 2013 (oral).
• Observation of a poloidal asymmetry of fluctuation perpendicular velocity measured by Doppler backscattering on Tore Supra plasmas
  
  • Storelli A.
  • Hennequin Pascale
  • Vermare Laure
  • Gürcan Özgür D.
  • Tore Supra Team
  , 2013 (oral).
• Spatial propagation of turbulence and formation of mesoscopic structures in GK simulations
  
  • Dif-Pradalier Guilhem
  • Ghendrih Ph.
  • Diamond P.H.
  • Garbet X.
  • Grandgirard V.
  • Palermo F.
  • Sarazin Y.
  • Strugarek Antoine
  • Abitboul J.
  • Gürcan Özgür D.
  • Hennequin Pascale
  • Morel Pierre
  • Vermare Laure
  , 2013 (http://ttf2013.ucsd.edu/TTF_Meeting/Home.html).
• Geodesic acoustic modes:ffsimultaneous observation of density,ff magnetic-field, and flow componentsff in the TCV tokamak
  
  • Coda S.
  • de Meijere K.
  • Huang Z.
  • Vermare Laure
  • Vernay T.
  • Vuille V.
  • Brunner Stephan
  • Dominski J.
  • Hennequin Pascale
  • Krämer-Flecken A.
  • Merlo G.
  • Porte L.
  , 2013 (oral).
• Damping of Geodesic Acoustic Modes.
  
  • Vermare Laure
  • Hennequin Pascale
  • Gürcan Özgür D.
  • Morel Pierre
  • Tore Supra Team
  , 2013 (oral).
• Detection of thin current sheets and associated reconnection in the Earth's turbulent magnetosheath using cluster multi-point measurements
  
  • Chasapis A.
  • Retinò Alessandro
  • Sahraoui Fouad
  • Greco A.
  • Vaivads A.
  • Sundkvist D.
  • Canu Patrick
  , 2013, 15, pp.EGU2013-5796.
• Suprathermal electron acceleration at reconnection jet fronts and braking regions in the Earth's magnetotail
  
  • Retinò Alessandro
  • Vaivads A.
  • Zieger B.
  • Fujimoto M.
  • Kasahara S.
  • Nakamura R.
  • Chasapis A.
  • Fu H.S.
  , 2013, 15, pp.EGU2013-5627. Magnetic reconnection is an efficient mechanisms for accelerating charged particles to energies much higher than their thermal energy. Important examples are the solar corona and planetary magnetospheres. A number of recent numerical simulations as well as in situ observations in Earth's magnetotail indicate that strong acceleration occurs at reconnection jet fronts, the boundary separating jetting from ambient plasma, and in jet braking regions, where jets eventually stop/dissipate. Yet the details of the acceleration mechanisms are not fully understood. Here we present a few examples of jet fronts/braking regions and associated suprathermal electron acceleration in the Earth's magnetotail, by using Cluster spacecraft data. We discuss the properties of accelerated electrons and electromagnetic fields for both jet front and jet braking regions.
• A 3D parallel model of Ganymede's exosphere
  
  • Leclercq Ludivine
  • Turc Lucile
  • Leblanc François
  • Modolo Ronan
  , 2013, pp.EGU2013-9679. Ganymede is a unique object : it is the biggest moon of our solar system, and the only satellite which has its own intrinsic magnetic field. Its surface is covered by water ice and by regolith. Some previous observations suggest that below its surface may exist an ocean of liquid water. The atmosphere of the planet is poorly known but should be composed essentially of water, hydrogen and oxygen (Marconi et al., Icarus, 2007). These atmospheric particles mainly originate from the surface thanks to sublimation of water-ice and sputtering, a process driven by the magnetospheric Jovian particles impacting Ganymede surface and leading to ejection of atoms and molecules into Ganymede atmosphere. We developed a model of Ganymede's atmosphere based on a 3D Monte Carlo description of the fate of the ejected particles from the surface. This model has been parallelized allowing a much better statistical, spatial and temporal description of Ganymede's environment. This model includes the main sources of the neutral atmosphere and is able to calculate all its characteristics. It was successfully compared to the few known observations as well as to previous modeling. In this presentation, we will present the main characteristics of this model and what it tells us on Ganymede's atmosphere, in terms of spatial structure, composition, temporal variability and relations with both magnetosphere and surface.
• Formation of the Earth's Ion Foreshock in the quasi-perpendicular collisionless shock region: Full-particle 2D simulation results
  
  • Savoini Philippe
  • Lembège Bertrand
  • Stienlet J.
  , 2013, 15, pp.4978. The ion foreshock located upstream of the Earth's shock front is populated with ions having interacted with the shock and then are reflected back with an high energy gain. In situ spacecrafts measurements have firmly established the existence of two distinct populations in the foreshock usptream of quasi-perpendicular shock region (i.e. for 45° &#8804; &#920;Bn &#8804; 90°, where &#920;Bn is the angle between the shock normal and the upstream magnetostatic field): (i) field-aligned (FAB) ion beams characterized by a gyrotropic distribution, and (ii) gyro-phase bunched (GPB) ions characterized by a NON gyrotropic distribution, which exhibit a non-vanishing perpendicular bulk velocity. Then, the purpose of the present work is to identify the different possible sources of backstreaming ions and is based on the use of 2D PIC simulations of a curved shock, where full curvature effects, time of flight effects and both electrons and ions dynamics are fully described by a self consistent approach. Our analysis evidences that these two populations mentionned above may have different origins identified both in terms of interaction time and distance of penetration. In particular, ours simulations evidence that "GPB" and FAB populations are characterized by a short (&#916;Tinter = 1 to 2 tci) and much larger (&#916;Tinter = 1 to 10 tci) interaction time respectively, where tci is the upstream ion gyroperiod. A deeper analysis of both individual and statistical ion trajectories evidences that: (i) both populations can be discriminated in terms of injection angle into the shock front (i.e. defined between the normal to the shock front and the gyration velocity vector when ions reach the shock). Such a behavior explains how reflected ions can be splitted in the observed two populations "FAB" and "GPB". (ii) ion trajectories differ between the "FAB" and "GPB" populations at the shock front. In particular, FAB and GPB ions suffer respectively multi-bounces and one bounce only. (iii) the drift associated to the "FAB" ions allows them to scan a &#920;Bn range between 10° and 20° (in the quasi-perpendicular domain) which accounts for their gyrotropic distribution (loss of their initial gyro-phase which is not the case for the "GPB" ions). Consequences on parallel energy gain will be illustrated with particles trajectories typical of each population.
• Heavy ion dynamics at Mercury
  
  • Delcourt Dominique
  , 2013. The MESSENGER spacecraft was inserted into orbit about Mercury on March 18 2011. Particle measurements from the FIPS instrument onboard this spacecraft reveal abundant populations of heavy ions such as O and Na in all magnetospheric regions. These ions appear to significantly contribute to thermal pressure, particularly in the nightside equatorial region where they can account for up to one third of the proton pressure. These heavy ion populations that originate from the planet surface via a variety of processes (e.g., thermal desorption, solar wind sputtering, micro-meteoritic bombardment...) thus have to be considered for a comprehensive investigation of the magnetosphere structure and dynamics at Mercury. We will review some transport features of these heavy ions of planetary origin. These features include : large scale convection from dayside cusp to nightside plasma sheet and subsequent nonadiabatic transport in the magnetotail, impulsive energization during short-lived reconfigurations of the magnetosphere, as well as centrifugally stimulated escape from the exosphere. We will also discuss the fate of planetary ions entering into the magnetosphere from the magnetosheath and their ring-like distribution at low latitudes.
• Density Holes, Hot Flow Anomalies and SLAMS Upstream of Earth's Bow Shock
  
  • Parks G. K.
  • Lee E.
  • Lin N.
  • Canu Patrick
  • Fu Suiyan
  • Cao J.B.
  • Dandouras I.
  • Rème H.
  • Goldstein M. L.
  , 2013, 15, pp.EGU2013-5584. Density holes (DH), Hot Flow Anomalies (HFA) and Short Large Amplitude Magnetic Structures (SLAMS) are transient structures observed in the upstream region of Earth's bow shock. The densities in these structures are depleted and in some cases as much as 99% of the ambient solar wind (SW) density. Moreover, the velocity moments of the SW show slow down and diversion in front of these structures. These structures, which can be as short as 4s (spin period of the spacecraft), are seen only when back-streaming particles are present. But not all backstreaming particles produce upstream structures and the conditions for forming these structures still remain unknown. In 2010 and 2011, the Cluster plasma ion experiment was configured to sample 3D distributions of the SW and the backstreaming particles with spin period time resolution (4s). These results show the SW beam in the hole is persistent and that evolving structures can be produced within existing DHs, HFAs and SLAMS. We present new observations of upstream structures including examples of how the structures can evolve into shocks.
• Impact of the Earth bow shock crossing on magnetic clouds structure
  
  • Turc Lucile
  • Fontaine Dominique
  • Savoini Philippe
  • Kilpua E. K. J.
  , 2013, 15, pp.4848. In the solar wind, magnetic clouds (MC) display a well-defined magnetic structure. When they reach the vicinity of the Earth, their structure is modified by their interaction with the Earth environment. In this study, we focus on the bow shock crossing of MCs, and more specifically on how it alters their magnetic structure. We compare observations from the Cluster spacecraft in the magnetosheath to ACE magnetic field measurements in the solar wind, in order to highlight the differences before and after the bow shock crossing. We find that the magnetic field amplitude is higher inside the magnetosheath, as expected from the compression behind the shock, but that the magnetic field direction can exhibit different features. It can be similar to the solar wind magnetic field direction, display a phase shift or the smooth rotation can even disappear in the magnetosheath. The correlation between the variation of the magnetic field direction from the solar wind to the magnetosheath and the shock obliquity angle is investigated. Finally, a simple 3D MHD model is developed to describe the interaction of a MC with the bow shock and calculate the magnetic field amplitude and direction inside the magnetosheath. We show several outputs of the model, corresponding to different orientations of the MC axis. We compare these modeled cases to observations. In some cases, the results show that the trends are in qualitative agreement, and other cases are further discussed.