Publications

2014

• New Compact Hohlraum Configuration Research at the 1.7 MA Z-Pinch Generator
  
  • Kantsyrev Viktor L.
  • Chuvatin Alexandre S.
  • Rudakov Leonid I.
  • Velikovich A. L.
  • Shreshta I. K.
  • Esaulov A. A.
  • Safronova Alla S.
  • Shlyaptseva V. V.
  • Osborne Glenn C.
  • Astanovitsky A. L.
  • Weller Michael E.
  • Stafford A.
  • Schultz K. A.
  • Cooper M. C.
  • Cuneo Michael E.
  • Jones B.
  • Vesey R. A.
  , 2014, 1639, pp.102. A new compact Z-pinch x-ray hohlraum design with parallel-driven x-ray sources was experimentally demonstrated in a full configuration with a central target and tailored shine shields (to provide a symmetric temperature distribution on the target) at the 1.7 MA Zebra generator. This presentation reports on the joint success of two independent lines of research. One of these was the development of new sources planar wire arrays (PWAs). PWAs turned out to be a prolific radiator. Another success was the drastic improvement in energy efficiency of pulsed-power systems, such as the Load Current Multiplier (LCM). The Zebra/LCM generator almost doubled the plasma load current to 1.7 MA. The two above-mentioned innovative approaches were used in combination to produce a new compact hohlraum design for ICF, as jointly proposed by SNL and UNR. Good agreement between simulated and measured radiation temperature of the central target is shown. Experimental comparison of PWAs with planar foil liners (PFL) - another viable alternative to wire array loads at multi-MA generators show promising data. Results of research at the University of Nevada Reno allowed for the study of hohlraum coupling physics at University-scale generators. The advantages of new hohlraum design applications for multi-MA facilities with W or Au double PWAs or PFL x-ray sources are discussed. (10.1063/1.4904787)
  DOI : 10.1063/1.4904787
• The transition from symmetric to asymmetric collisionless magnetic reconnection
  
  • Hesse Michael
  • Aunai N.
  • Zenitani Seiji
  , 2014, 40, pp.D3.3-19-14. Magnetic reconnection at the Earth's magnetopause facilitates the transfer of mass, energy, and momentum from the solar wind into the Earth's magnetosphere. Owing to the variability of the solar wind plasma and magnetic field, the reconnection process typically involves different conditions on both inflow sides, but occasionally more symmetric conditions are encountered as well. Based on prior research we now know that the structure of the reconnection diffusion region depends substantially on the symmetry (or lack thereof) of the inflowing plasmas and magnetic fields. It is therefore of considerable interest to investigate the transition of one scenario to the other - in particular for the purpose of understanding the role of plasma mixing, heating, and of features such as pressure nongyrotropies. This presentation will focus on recent theory and modeling results pertaining to these topics, and it will illuminate the means by which these kinetic processes play a role in determining the reconnection rate.
• Langmuir turbulence excited by an electron beam in a plasma with long-wave density fluctuations
  
  • Volokitin A.
  • Krasnoselskikh V.
  • Krafft C.
  , 2014, 40, pp.D3.4-14-14. The interaction of the electron beam propagating in a nonuniform solar wind plasma with Langmuir waves is considered. Plasma waves are described one dimensional system of Zakharov equations, the beam dynamics is modeled using particles moving in the total electric field of the Langmuir waves. The role of external plasma density fluctuations, which are known to be present in the solar wind, is taking into account. It is shown that at low density fluctuations delta n /n₀ <3k(2) L_d(2) , relaxation of the beam happen in the same way as in a homogeneous plasma and can be described in the frame of a quasi-linear (QL) theory. In this case, the relaxation length of the beam is small and corresponds to obtained in the quasi-linear approximation. Conversely, when the level of fluctuation of density exceeds a certain threshold, i.e. 1>delta n /n₀ >3k(2) L_d(2) , plasma inhomogeneity has a decisive influence on the relaxation process. First, the growth of waves on the linear stage becomes localized, thereby clearly identifiable wave packets or clumps dominate the wave spectrum. This effect is due to the kinematics of wave propagation in conjunction with the resonant wave-particle interaction. The wave's packets start to grow more likely in regions of high density gradients. The second important feature in the relaxation of the beam in an inhomogeneous plasma is to build distribution of accelerated electrons with velocities exceeds the initial drift velocity of the beam. In this case the velocity distribution of electrons in the beam expands in the both direction to lower and higher velocities, the density of the accelerated electrons can reach more than 10 ÷ 20% of the beam density and the flux of energy in the group accelerated particles reaches 40% or more of the initial beam energy flux. In addition, the wave profiles obtained in the simulation results are in good agreement with the observed in situ on the spacecraft STEREO and others who show frequent presence of spatially localized Langmuir waves in the solar wind and correlated with the presence of superthermal electrons during type III radio bursts or in electron foreshock regions. Finally the processes of nonlinear parametric decay of Langmuir wave packets waves in an inhomogeneous plasma with the participation of ion-acoustic is considered on the base of the simulations.
• The Radio & Plasmas Waves instrument on the Solar Orbiter mission : science objectives and capabilities
  
  • Maksimovic M.
  • Krasnoselskikh V.
  • Bale S. D.
  • Soucek J.
  • Vaivads A.
  • Chust Thomas
  • Steller M.
  • Travnicek Pavel
  , 2014, 40, pp.D2.3-29-14. We review firstly the science objectives of the Radio & Plasmas Waves (RPW) instrument on the Solar Orbiter mission. Among those the study of the connectivity between the solar corona and the inner Heliosphere as close as from 0.3 AU and the kinetic behavior of the Solar Wind are of prime importance. We present then the RPW technical capabilities which will allow in-situ and remote sensing measurements of both electrostatic and electromagnetic fields and waves in a broad frequency
• Innovative particle detector for future heliophysics missions
  
  • Berthomier Matthieu
  • Techer Jean-Denis
  • Morel Xavier
  , 2014, 40, pp.D2.3-28-14. Innovative particle detectors are needed for future heliophysics missions in order to access to high-time resolution phenomena within limited resources. One of the main challenges is to accurately monitor solar wind plasmas from non-spinning platforms. Such an innovative particle detector which is based on a new optical concept allows the coverage of 4pi str solid angle with only two sensor heads. It fits the need of all-sky thermal plasma measurements on three axis stabilized spacecraft which are the most commonly used platforms for heliophysics missions with imaging capabilities. This 3D field-of-view plasma analyzer also takes advantage of the new possibilities offered by the development of an ultra low-power multichannel charge sensitive amplifier used for the imaging detector of the instrument. We present the design and measured performances of a prototype model that will fly on a test rocket in 2014. One of the possible applications of this innovative particle detector is the investigation of electron time scale phenomena in the turbulent solar wind of the inner heliosphere with unprecedented time resolution below 10 msec.
• Energy and frequency dependence of the alpha particle redistribution produced by internal kink modes
  
  • Farengo R.
  • Ferrari H. E.
  • Garcia-Martinez P. L.
  • Firpo Marie-Christine
  • Ettoumi Wahb
  • Lifschitz Agustin
  Physics of Plasmas, American Institute of Physics, 2014, 21 (8), pp.082512. The redistribution of alpha particles due to internal kink modes is studied. The exact particle trajectories in the total fields, equilibrium plus perturbation, are calculated. The equilibrium has circular cross section and the plasma parameters are similar to those expected in ITER. The alpha particles are initially distributed according to a slowing down distribution function and have energies between 18 keV and 3.5 MeV. The (1, 1), (2, 2), and (2, 1) modes are included and the effect of changing their amplitude and frequency is studied. When only the (1, 1) mode is included, the spreading of high energy ( E≳1 MeV) alpha particles increases slowly with the energy and mode frequency. At lower energies, the redistribution is more sensitive to the mode frequency and particle energy. When a (2, 1) mode is added, the spreading increases significantly and particles can reach the edge of the plasma. Trapped particles are the most affected and the redistribution parameter can have maxima above 1 MeV, depending on the mode frequency. These results can have important implications for ash removal. (10.1063/1.4893145)
  DOI : 10.1063/1.4893145
• A Multi Water Bag model of drift kinetic electron plasma
  
  • Morel Pierre
  • Ghiro Florent Dreydemy
  • Berionni Vincent
  • Coulette David
  • Besse Nicolas
  • Gürcan Özgür D.
  The European Physical Journal D : Atomic, molecular, optical and plasma physics, EDP Sciences, 2014, 68 (8). A Multi Water Bag model is proposed for describing drift kinetic plasmas in a magnetized cylindrical geometry, relevant for various experimental devices, solar wind modeling ... The Multi Water Bag (MWB) model is adapted to the description of a plasma with kinetic electrons as well as an arbitrary number of kinetic ions. This allows to describe the kinetic dynamics of the electrons, making possible the study of electron temperature gradient (ETG) modes, in addition to the effects of non adiabatic electrons on the ion temperature gradient (ITG) modes, that are of prime importance in the magnetized plasmas micro-turbulence [X. Garbet, Y. Idomura, L. Villard, T.H. Watanabe, Nucl. Fusion 50, 043002 (2010); J.A. Krommes, Ann. Rev. Fluid Mech. 44, 175 (2012)]. The MWB model is shown to link kinetic and fluid descriptions, depending on the number of bags considered. Linear stability of the ETG modes is presented and compared to the existing results regarding cylindrical ITG modes [P. Morel, E. Gravier, N. Besse, R. Klein, A. Ghizzo, P. Bertrand, W. Garbet, Ph. Ghendrih, V. Grandgirard, Y. Sarazin, Phys. Plasmas 14, 112109 (2007)]. (10.1140/epjd/e2014-50165-8)
  DOI : 10.1140/epjd/e2014-50165-8
• Development and test of the negative and positive ion thruster PEGASES
  
  • Aanesland Ane
  • Rafalskyi D.V.
  • Lafleur Trevor
  • Grondein Pascaline
  • Chabert Pascal
  • Mazouffre Stéphane
  • Renaud Denis
  • Garrigues Laurent
  • Hagelaar G J M
  • Levko Dimitry
  , 2014 (AIAA-2014-3424). (10.2514/6.2014-3424)
  DOI : 10.2514/6.2014-3424
• Design and Preliminary Testing Plan of Electronegative Ion Thruster
  
  • Schloeder N.R.
  • Lui T.
  • Walker M.L.
  • Polzin K.A.
  • Dankanich J.
  • Aanesland Ane
  , 2014 (AIAA-2014-3425). (10.2514/6.2014-3425)
  DOI : 10.2514/6.2014-3425
• Mechanisms of Discharge in Liquids
  
  • Rousseau Antoine
  , 2014.
• Deposition of semiconductive films in SF6 ion-ion plasma
  
  • Rafalskyi D.V.
  • Aanesland Ane
  , 2014.
• Parameter mapping of ion-ion plasma formation downstream localized magnetic barriers in Ar/SF6 mixtures
  
  • Grondein Pascaline
  • Bredin Jérôme
  • Chabert Pascal
  • Aanesland Ane
  , 2014.
• Ion-ion plasma potential control at alternate ion-ion beam extraction
  
  • Rafalskyi D.V.
  • Aanesland Ane
  , 2014.
• Diagnostic and applications of ion-ion plasmas
  
  • Aanesland Ane
  • Rafalskyi D.V.
  • Bredin Jérôme
  , 2014.
• Living on the edge: fifteen years un RF sheaths (Crookes Prize Lecture)
  
  • Chabert Pascal
  , 2014.
• Inductively-coupled plasmas (ICP) of Cl<SUB>2</SUB>, O<SUB>2</SUB> and mixtures : measurements of atoms, ClxOy and electron densit
  
  • Foucher Mickaël
  • Carbone Emile
  • Booth Jean-Paul
  • Chabert Pascal
  , 2014.
• High sensitivity ultra-broad-band absorption spectroscopy applied to etching plasmas
  
  • Foucher Mickaël
  • Carbone Emile
  • Booth Jean-Paul
  • Chabert Pascal
  , 2014.
• Experimental demonstration of the PEGASES plasma thruster concept
  
  • Lafleur Trevor
  • Rafalskyi D.V.
  • Aanesland Ane
  , 2014.
• Electrostatic probe and laser photodetachment measurements in the hydrogen negative ion (H-) source "Prometheus I
  
  • Aleiferis S.
  • Svarnas P.
  • Tsiroudis I.
  • Béchu Stéphane
  • Lacoste A.
  • Bacal M.
  , 2014, pp.sciencesconf.org:gd2014:27348.
• Modulation of ionization front propagation velocity in a µs plasma gun helium discharge with nitrogen admixture
  
  • Darny Thibault
  • Robert Eric
  • Pechereau François
  • Bourdon Anne
  • Dozias Sébastien
  • Pouvesle Jean-Michel
  , 2014. The propagation velocity modification of μs helium plasma gun (PG) discharge with nitrogen gas admixture in the helium buffer is studied in relation with ionization front imaging and helium-nitrogen plasma features. From 0,1 % to 0,8 % of N2, the ionization front is faster, more extended and with strong luminous intensity, compared to the high purity helium. The velocity has an optimum, for approximately 0,3 % of N2. Above 0,3 %, the velocity is progressively slowing down, and finally gets slower than the pure helium case above 0,9 %. The velocity evolution may be linked with kinetic and energy transfer predominantly on N2+ or N2 according to the increase of N2 %. Consequently, a local reinforcement of electric field in the front of the discharge is suspected for low N2 percentage, involving velocity increase of the discharge.
• Superparamagnetic nanoparticle detection using gradiometer induction sensors for intraoperative localization tumor tool
  
  • Mohamadabadi Kaveh
  • Simon Hervé
  • Coillot Christophe
  • Goze-Bac Christophe
  • Pourroy Geneviève
  , 2014. Our study concerns nano-objects consisting in an iron oxide core of 10(±2) nm or 20(±5) nm size, which exhibit superparamagnetic behavior, whose shell is constituted of dendrons carrying a dye. The characterization of the magnetic properties of these nano-objects together with their relaxivity into MRI will be presented in this poster. Their detection in an intraoperative context requires an instrument able to detect the extremely weak magnetic signature of the superparamagnetic nanoparticle in a noisy environment. A magnetic probe based on an AC magnetic field excitation of the nano-object coupled to an inductive gradiometer sensor has been designed to achieve this measurement. A conductive layer surrounding the probe is used to provide a shielding, thanks to the eddy current which will limit the leakage magnetic field outside of the probe. The principle of the probe and its ability to measure the magnetic signature of the magnetic nano-objects will be discussed.
• Radiation-hardened and low-noise ASIC amplifier designed for the highly sensitive ESA/JUICE induction magnetometer
  
  • Rhouni Amine
  • Sou Gérard
  • Mansour Malik
  • Coillot Christophe
  , 2014.
• Large scale Tesla coil guided discharges initiated by femtosecond laser filamentation in air
  
  • Arantchouk Léonid
  • Point Guillaume
  • Brelet Yohann
  • Prade Bernard
  • Carbonnel Jérôme
  • André Yves-Bernard
  • Mysyrowicz André
  • Houard Aurélien
  Journal of Applied Physics, American Institute of Physics, 2014, 116, pp.13303. The guiding of meter scale electric discharges produced in air by a Tesla coil is realized in laboratory using a focused terawatt laser pulse undergoing filamentation. The influence of the focus position, the laser arrival time or the gap length is studied to determine the best conditions for efficient laser guiding. Discharge parameters such as delay, jitter and resistance are characterized. An increase of the discharge length by a factor 5 has been achieved with the laser filaments, corresponding to a mean breakdown field of 2 kV/cm for a 1.8 m gap length. Consecutive guided discharges at a repetition rate of 10 Hz are also reported. (10.1063/1.4886582)
  DOI : 10.1063/1.4886582
• An axially propagating two-stream instability in the Hall thruster plasma
  
  • Tsikata S.
  • Cavalier Jordan
  • Héron A.
  • Honoré Cyrille
  • Lemoine Nicolas
  • Grésillon D.
  • Coulette David
  Physics of Plasmas, American Institute of Physics, 2014, 21 (7), pp.072116. Collective Thomson scattering experiments reveal the presence of high-frequency, axial electron density fluctuations at millimetric wavelengths in the Hall thruster plasma. The properties of these fluctuations are investigated experimentally and via linear kinetic theory. The relative drift of electrons and ions in the axial direction is found to be insufficient to cause excitation of the observed mode. Instead, the mode is determined to be a two-stream instability arising due to the velocity difference between singly and doubly charged ion populations in the plume. (10.1063/1.4890025)
  DOI : 10.1063/1.4890025
• Review of kinetic turbulence in collisionless space plasmas
  
  • Sahraoui Fouad
  , 2014.