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  • 1.
    Andres, N.
    et al.
    Univ Paris Sud, Sorbonne Univ, Lab Phys Plasmas, CNRS,Ecole Polytech,Observ Paris, F-91128 Palaiseau, France.
    Sahraoui, F.
    Univ Paris Sud, Sorbonne Univ, Lab Phys Plasmas, CNRS,Ecole Polytech,Observ Paris, F-91128 Palaiseau, France.
    Galtier, S.
    Univ Paris Sud, Sorbonne Univ, Lab Phys Plasmas, CNRS,Ecole Polytech,Observ Paris, F-91128 Palaiseau, France;Univ Paris Saclay, Univ Paris Sud, Paris, France.
    Hadid, Lina Z
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Dmitruk, P.
    UBA, CONICET, Inst Fis Buenos Aires, Ciudad Univ, RA-1428 Buenos Aires, DF, Argentina.
    Mininni, P. D.
    Univ Buenos Aires, Fac Ciencias Exactas & Nat, Dept Fis, Ciudad Univ, RA-1428 Buenos Aires, DF, Argentina.
    Energy cascade rate in isothermal compressible magnetohydrodynamic turbulence2018In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 84, no 4, article id 905840404Article in journal (Refereed)
    Abstract [en]

    Three-dimensional direct numerical simulations are used to study the energy cascade rate in isothermal compressible magnetohydrodynamic turbulence. Our analysis is guided by a two-point exact law derived recently for this problem in which flux, source, hybrid and mixed terms are present. The relative importance of each term is studied for different initial subsonic Mach numbers M-S and different magnetic guide fields B-0. The dominant contribution to the energy cascade rate comes from the compressible flux, which depends weakly on the magnetic guide field B-0, unlike the other terms whose moduli increase significantly with M s and B-0. In particular, for strong B-0 the source and hybrid terms are dominant at small scales with almost the same amplitude but with a different sign. A statistical analysis undertaken with an isotropic decomposition based on the SO(3) rotation group is shown to generate spurious results in the presence of B-0, when compared with an axisymmetric decomposition better suited to the geometry of the problem. Our numerical results are compared with previous analyses made with in situ measurements in the solar wind and the terrestrial magnetosheath.

  • 2. Andrushchenko, Zhanna N.
    et al.
    Jucker, Martin
    Pavlenko, Vladimir P.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Self-consistent model of electron drift mode turbulence2008In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 74, no 1, p. 21-33Article in journal (Refereed)
    Abstract [en]

    The nonlinear dynamics of magnetic electron drift mode turbulence are outlined and the generation of large-scale magnetic Structures in a non-uniform magnetized plasma by turbulent Reynolds stress is demonstrated. The loop-back of large-scale flows on the microturbulence is elucidated and the modulation of the electron drift mode turbulence spectrum in a, medium with slowly varying parameters is presented. The wave kinetic equation in the presence of large-scale flows is derived and it can be seen that the small-scale turbulence and the large-scale structures form a, self-regulating system. Finally. it is shown by the use of quasilinear theory that the shearing of microturbulence by the flows can be described by a diffusion equation in k-space and the corresponding diffusion coefficients are calculated.

  • 3.
    Asp, Elina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Pavlenko, Vladimir P.
    Revenchuk, Sergey M.
    Stability of the Landau Resonance for Drift Modes in Rotating Tokamak Plasma2003In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 60, no 5, p. 371-Article in journal (Refereed)
    Abstract [en]

    The linear stability of drift waves in a poloidally rotating tokamak plasma is considered. The derived dispersion relation features a peaking of the diamagnetic frequency which gives the drift modes an irreducible two-dimensional character. We then show that inverse Landau damping can be suppressed and even stabilized, if the flow's shear is strong. Even though the instability, excited by the Landau resonance, is stronger at a high velocity shear for positive rotation velocities, effects due to the rotation of the plasma can reverse the sign and induce damping of the two-dimensional drift modes. This stabilizing mechanism works only for positive rotation velocities. For negative rotation velocities, we show that only modes with high poloidal mode numbers are unstable.

  • 4.
    Brunetti, Daniele
    et al.
    CNR, IFP, Milan, Italy.
    Graves, J. P.
    SPC, Lausanne, Switzerland.
    Lazzaro, E.
    CNR, IFP, Milan, Italy.
    Mariani, A.
    CNR, IFP, Milan, Italy.
    Nowak, S.
    CNR, IFP, Milan, Italy.
    Cooper, W. A.
    SPC, Lausanne, Switzerland.
    Wahlberg, Christer
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Analytic study on low-n external ideal infernal modes in tokamaks with large edge pressure gradients2018In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 84, no 2, article id 745840201Article in journal (Refereed)
    Abstract [en]

    The problem of pressure driven infernal type perturbations near the plasma edge is addressed analytically for a circular limited tokamak configuration which presents an edge flattened safety factor. The plasma is separated from a metallic wall, either ideally conducting or resistive, by a vacuum region. The dispersion relation for such types of instabilities is derived and discussed for two classes of equilibrium profiles for pressure and mass density.

  • 5.
    Chapman, I. T.
    et al.
    Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England;Culham Sci Ctr, CCFE, Abingdon OX14 3DB, Oxon, England;Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, Oxon, England.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Militello Asp, Elina
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Inst Plasma Phys & Laser Microfus, PL-01497 Warsaw, Poland.
    The merits of ion cyclotron resonance heating schemes for sawtooth control in tokamak plasmas2015In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 81, article id 365810601Article in journal (Refereed)
    Abstract [en]

    JET experiments have compared the efficacy of low-and high field side ion cyclotron resonance heating (ICRH) as an actuator to deliberately minimise the sawtooth period. It is found that low-field side ICRH with low minority concentration is optimal for saw tooth control for two main reasons. Firstly, low-field side heating means that any toroidal phasing of the ICRH (-90 degrees, +90 degrees or dipole) has a destabilising effect on the sawteeth, meaning that dipole phasing can be employed, since tins is preferable due to less plasma wall interaction from Resonant Frequency (RI) sheaths. Secondly, the resonance position of the low field side ICRH does not have to be very accurately placed to achieve saw tooth control, relaxing the requirement for real-time control of the RF frequency. These empirical observations have been confirmed by hybrid kinetic-magnetohydrodynamic modelling, and suggest that the ICRH antenna design for ITER is well positioned to provide a control actuator capable of having a significant effect on the sawtooth behaviour.

  • 6. Gedalin, M.
    et al.
    Spitkovsky, A.
    Medvedev, M.
    Balikhin, M.
    Krasnoselskikh, V.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Perri, S.
    Relativistic filamentary equilibria2011In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 77, p. 193-205Article in journal (Refereed)
    Abstract [en]

    Plasma filamentation is often encountered in collisionless shocks and inertial confinement fusion. We develop a general analytical description of the two-dimensional relativistic filamentary equilibrium and derive the conditions for existence of potential-free equilibria. A pseudopotential equation for the vector-potential is constructed for cold and relativistic Maxwellian distributions. The role of counter-streaming is explained. We present single current sheet and periodic current sheet solutions, and analyze the equilibria with electric potential. These solutions can be used to study linear and nonlinear evolution of the relativistic filamentation instability.

  • 7.
    Gedalin, Michael
    et al.
    Bengur Univ Negev, Dept Phys, Beer Sheva, Israel..
    Dimmock, Andrew P.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Russell, Christopher T.
    Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA USA..
    Pogorelov, Nikolai V.
    Univ Alabama Huntsville, Ctr Space Plasma & Aeron Res, Huntsville, AL 35805 USA..
    Roytershteyn, Vadim
    Space Sci Inst, Boulder, CO 80301 USA..
    Role of the overshoot in the shock self-organization2023In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 89, no 2, article id 905890201Article in journal (Refereed)
    Abstract [en]

    A collisionless shock is a self-organized structure where fields and particle distributions are mutually adjusted to ensure a stable mass, momentum and energy transfer from the upstream to the downstream region. This adjustment may involve rippling, reformation or whatever else is needed to maintain the shock. The fields inside the shock front are produced due to the motion of charged particles, which is in turn governed by the fields. The overshoot arises due to the deceleration of the ion flow by the increasing magnetic field, so that the drop of the dynamic pressure should be compensated by the increase of the magnetic pressure. The role of the overshoot is to regulate ion reflection, thus properly adjusting the downstream ion temperature and kinetic pressure and also speeding up the collisionless relaxation and reducing the anisotropy of the eventually gyrotropized distributions.

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  • 8.
    Hadid, L. Z.
    et al.
    Univ Paris Saclay, Lab Phys Plasmas LPP, CNRS, Observ Paris,Sorbonne Univ,Inst Polytech Paris,Ec, F-91120 Palaiseau, France..
    Shebanits, Oleg
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Space Plasma Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. Imperial Coll London, Blackett Lab, London SW7 2AZ, England..
    Wahlund, J-E
    Swedish Inst Space Phys, Box 537, SE-75121 Uppsala, Sweden..
    Morooka, Michiko
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Nagy, A. F.
    Univ Michigan, Climate & Space Sci & Engn, Ann Arbor, MI 48109 USA..
    Farrell, W. M.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Holmberg, M. K. G.
    ESTEC ESA, NL-2201 AZ Noordwijk, Netherlands..
    Modolo, R.
    LATMOS Lab Atmospheres Milieux Observat Spatiales, F-78280 Guyancourt, France..
    Persoon, A. M.
    Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA..
    Tseng, W. L.
    Natl Taiwan Normal Univ, Dept Earth Sci, Taipei 11677, Taiwan..
    Ye, S-Y
    Southern Univ Sci & Technol SUSTech, Dept Earth & Space Sci, Shenzhen 518055, Peoples R China..
    Ambipolar electrostatic field in negatively charged dusty plasma2022In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 88, no 2, article id 555880201Article in journal (Refereed)
    Abstract [en]

    We study the effect of negatively charged dust on the magnetic-field-aligned polarisation electrostatic field (E-parallel to) using Cassini's RPWS/LP in situ measurements during the `ring-grazing' orbits. We derive a general expression for E-parallel to and estimate for the first time in situ parallel to E-parallel to parallel to (approximately 10(-5) V m(-1)) near the Janus and Epimetheus rings. We further demonstrate that the presence of the negatively charged dust close to the ring plane (vertical bar Z vertical bar less than or similar to 0.11 R-s) amplifies parallel to E-parallel to parallel to by at least one order of magnitude and reverses its direction due to the effect of the charged dust gravitational and inertial forces. Such reversal confines the electrons at the magnetic equator within the dusty region, around 0.047 R-s above the ring plane. Furthermore, we discuss the role of the collision terms, in particular the ion-dust drag force, in amplifying E-parallel to. These results imply that the charged dust, as small as nanometres in size, can have a significant influence on the plasma transport, in particular ambipolar diffusion along the magnetic field lines, and so their presence must be taken into account when studying such dynamical processes.

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  • 9. Lapenta, Giovanni
    et al.
    Markidis, Stefano
    Divin, Andrey
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Newman, David
    Goldman, Martin
    Separatrices: The crux of reconnection2015In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 81, article id 325810109Article in journal (Refereed)
    Abstract [en]

    Magnetic reconnection is one of the key processes in astrophysical and laboratory plasmas: it is the opposite of a dynamo. Looking at energy, a dynamo transforms kinetic energy in magnetic energy while reconnection takes magnetic energy and returns it to its kinetic form. Most plasma processes at their core involve first storing magnetic energy accumulated over time and then releasing it suddenly. We focus here on this release. A key concept in analysing reconnection is that of the separatrix, a surface (line in 2D) that separates the fresh unperturbed plasma embedded in magnetic field lines not yet reconnected with the hotter exhaust embedded in reconnected field lines. In kinetic physics, the separatrices become a layer where many key processes develop. We present here new results relative to the processes at the separatrices that regulate the plasma flow, the energization of the species, the electromagnetic fields and the instabilities developing at the separatrices.

  • 10.
    Moiseenko, V. E.
    et al.
    Natl Sci Ctr Kharkiv Inst Phys & Technol, UA-61108 Kharkiv, Ukraine.;Kharkov Natl Univ, UA-61022 Kharkiv, Ukraine.;Uppsala Univ, Angstrom Lab, S-75237 Uppsala, Sweden.
    Chernitskiy, S. V.
    Westinghouse Elect Co LLC, Cranberry Twp, PA 16066 USA.
    Ågren, Olov
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Garkusha, I. E.
    Natl Sci Ctr Kharkiv Inst Phys & Technol, UA-61108 Kharkiv, Ukraine.;Kharkov Natl Univ, UA-61022 Kharkiv, Ukraine.
    Stellarator-mirror fusion-fission hybrid - a fast route to clean and safe nuclear energy2023In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 89, no 4, article id 955890401Article in journal (Refereed)
    Abstract [en]

    The multiple-recycle fuel cycle for uranium-238 considered here, if practically realized, can bring revolutionary changes in nuclear energy. A full use of uranium-238 implies a practically infinite resource for power generation. Besides the energy, the fuel cycle net output is only fission products, which are co-products rather than waste. For the same amount of energy produced, the amount of fission products is two orders of magnitude less compared with the amount of spent nuclear fuel generated in currently exploited nuclear energy production scenarios. Using the simplest isotope balance model, key features of the multiple-recycle fuel cycle for uranium-238 are investigated. The repetition of this cycle results in smooth transformation of the initial fuel to 'stationary' fuel without strong variations in the fractional isotope content. Deficit of delayed neutrons is a threat of the fuel cycle considered as well as other fuel cycles that use plutonium. It has a dramatic impact on reactor controllability and safety. A solution to this threat could be a subcritical nuclear reactor with an external neutron source. In this paper, use of a stellarator-mirror (SM) fusion-fission hybrid for the multiple-recycle fuel cycle for uranium-238 is analysed. A summary of the experimental and theoretical studies on the SM hybrid is given. Preliminary results for principal design of a SM hybrid nuclear reactor for the multiple-recycle fuel cycle for uranium-238 are presented.

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    FULLTEXT01
  • 11.
    Moiseenko, Vladimir E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    Ågren, Olov
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    A numerical model for radiofrequency heating of sloshing ions in a mirror trap2006In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 72, no 6, p. 1133-1137Article in journal (Refereed)
    Abstract [en]

    A newly developed numerical model calculating the distribution and damping of radiofrequency fields by sloshing ions is presented. The model solves time-harmonic Maxwell's equations written in terms of the electric field. It uses a two-dimensional grid and a Fourier series in the third coordinate and is based on a non-staggered mesh not aligned along the steady magnetic field. The numerical stability of the scheme is discussed, and the convergence analysis is presented.

  • 12.
    Moiseyenko, Volodymyr
    et al.
    Institute of Plasma Physics of the National Science Center “Kharkiv Institute of Physics and Technology”, Kharkiv, Ukraine.
    Kovtun, Yu. V.
    Wauters, T.
    Goriaev, A.
    Lyssoivan, A. I.
    Lozin, A. V.
    Pavlichenko, R. O.
    Shapoval, A. N.
    Maznichenko, S. M.
    Korovin, V. B.
    Kramskoy, E. D.
    Kozulya, M. M.
    Zamanov, N. V.
    Siusko, Y. V.
    Krasiuk, A. Yu.
    Romanov, V. S.
    Alonso, A.
    Brakel, R.
    Dinklage, A.
    Hartmann, D.
    Kazakov, Ye.
    Laqua, H.
    Ongena, J.
    Stange, T.
    First experiments on ICRF discharge generation by a W7-X-like antenna in the Uragan-2M stellarator2020In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 86, no 5, article id 905860517Article in journal (Refereed)
  • 13. Olshevsky, Vyacheslav
    et al.
    Lapenta, Giovanni
    Markidis, Stefano
    Divin, Andrey
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Role of Z-pinches in magnetic reconnection in space plasmas2015In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 81, article id 325810105Article in journal (Refereed)
    Abstract [en]

    A widely accepted scenario of magnetic reconnection in collisionless space plasmas is the breakage of magnetic field lines in X-points. In laboratory, reconnection is commonly studied in pinches, current channels embedded into twisted magnetic fields. No model of magnetic reconnection in space plasmas considers both nullpoints and pinches as peers. We have performed a particle-in-cell simulation of magnetic reconnection in a three-dimensional configuration where null-points are present initially, and Z-pinches are formed during the simulation along the lines of spiral null-points. The non-spiral null-points are more stable than spiral ones, and no substantial energy dissipation is associated with them. On the contrary, turbulent magnetic reconnection in the pinches causes the magnetic energy to decay at a rate of similar to 1.5% per ion gyro period. Dissipation in similar structures is a likely scenario in space plasmas with large fraction of spiral null-points.

  • 14. Peng, Ivy Bo
    et al.
    Vencels, Juris
    Lapenta, Giovanni
    Divin, Andrey
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Laure, Erwin
    Markidis, Stefano
    Energetic particles in magnetotail reconnection2015In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 81, article id 325810202Article in journal (Refereed)
    Abstract [en]

    We carried out a 3D fully kinetic simulation of Earth's magnetotail magnetic reconnection to study the dynamics of energetic particles. We developed and implemented a new relativistic particle mover in iPIC3D, an implicit Particle-in-Cell code, to correctly model the dynamics of energetic particles. Before the onset of magnetic reconnection, energetic electrons are found localized close to current sheet and accelerated by lower hybrid drift instability. During magnetic reconnection, energetic particles are found in the reconnection region along the x-line and in the separatrices region. The energetic electrons are first present in localized stripes of the separatrices and finally cover all the separatrix surfaces. Along the separatrices, regions with strong electron deceleration are found. In the reconnection region, two categories of electron trajectory are identified. First, part of the electrons are trapped in the reconnection region, bouncing a few times between the outflow jets. Second, part of the electrons pass the reconnection region without being trapped. Different from electrons, energetic ions are localized on the reconnection fronts of the outflow jets.

  • 15.
    Perri, S.
    et al.
    Univ Calabria, Dipartimento Fis, Via P Bucci 87036, Arcavacata Di Rende, Italy.
    Perrone, D.
    ASI Italian Space Agcy, Via Politecn Snc, Rome, Italy.
    Yordanova, Emiliya
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Sorriso-Valvo, L.
    Escuela Politec Nacl, Dept Fis, Av Ladron de Guevara 253, Quito 170517, Ecuador;CNR, ISTP, Via Amendola 122-D, I-70126 Bari, Italy.
    Paterson, W. R.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA.
    Gershman, D. J.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA.
    Giles, B. L.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA.
    Pollock, C. J.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA.
    Dorelli, J. C.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA.
    Avanov, L. A.
    NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA.
    Lavraud, B.
    Univ Toulouse, CNES, UPS, Inst Rech Astrophys & Planetol,CNRS, 9 Ave Colonel Roche, F-31400 Toulouse, France.
    Saito, Y.
    JAXA, Tokyo 1828522, Japan.
    Nakamura, R.
    Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria.
    Fischer, D.
    Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria.
    Baumjohann, W.
    Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria.
    Plaschke, F.
    Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria.
    Narita, Y.
    Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria.
    Magnes, W.
    Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria.
    Russell, C. T.
    Univ Calif Los Angeles, Inst Geophys & Planetary Phys, 603 CE Young Dr East, Los Angeles, CA 90095 USA.
    Strangeway, R. J.
    Univ Calif Los Angeles, Inst Geophys & Planetary Phys, 603 CE Young Dr East, Los Angeles, CA 90095 USA.
    Le Contel, O.
    Univ Paris Sud, Sorbonne Univ, Ecole Polytech, Observ Paris,Lab Phys Plasmas,CNRS, Route Saclay, F-91128 Palaiseaux, France.
    Khotyaintsev, Yuri V.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Valentini, F.
    Univ Calabria, Dipartimento Fis, Via P Bucci 87036, Arcavacata Di Rende, Italy.
    On the deviation from Maxwellian of the ion velocity distribution functions in the turbulent magnetosheath2020In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 86, no 1, article id 905860108Article in journal (Refereed)
    Abstract [en]

    The deviation from thermodynamic equilibrium of the ion velocity distribution functions (VDFs), as measured by the Magnetospheric Multiscale (MMS) mission in the Earth's turbulent magnetosheath, is quantitatively investigated. Making use of the unprecedented high-resolution MMS ion data, and together with Vlasov-Maxwell simulations, this analysis aims at investigating the relationship between deviation from Maxwellian equilibrium and typical plasma parameters. Correlations of the non-Maxwellian features with plasma quantities such as electric fields, ion temperature, current density and ion vorticity are found to be similar in magnetosheath data and numerical experiments, with a poor correlation between distortions of ion VDFs and current density, evidence that questions the occurrence of VDF departure from Maxwellian at the current density peaks. Moreover, strong correlation has been observed with the magnitude of the electric field in the turbulent magnetosheath, while a certain degree of correlation has been found in the numerical simulations and during a magnetopause crossing by MMS. This work could help shed light on the influence of electrostatic waves on the distortion of the ion VDFs in space turbulent plasmas.

  • 16. Sandberg, Ingmar
    et al.
    Pavlenko, Vladimir
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Astronomy and Space Physics.
    Zonal flow in toroidal ion temperature gradient mode turbulence2007In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 73, no 4, p. 565-573Article in journal (Refereed)
    Abstract [en]

    The properties of zonal flows in the toroidal ion temperature gradient mode turbulence are investigated taking into account the polarization drift effects. The stability criterion and the characteristic oscillation frequency of the zonal flow are determined in terms of the spectra of turbulent fluctuations. The nonlinear evolution of zonal flows may lead to the formation of stationary long-lived coherent structures supporting stationary shear layers. These results indicate the existence of regions with reduced levels of anomalous transport attributed to zonal flows generalizing previous findings regarding zonal flows in electron drift turbulence.

  • 17. Trines, R. M. G. M.
    et al.
    Bingham, R.
    Silva, L. O.
    Mendonca, J. T.
    Shukla, P. K.
    Murphy, C. D.
    Dunlop, M. W.
    Davies, J. A.
    Bamford, R.
    Vaivads, Andris
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Norreys, P. A.
    Applications of the wave kinetic approach: from laser wakefields to drift wave turbulence2010In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 76, no 6, p. 903-914Article in journal (Refereed)
    Abstract [en]

    Nonlinear wave-driven processes in plasmas are normally described by either a monochromatic pump wave that couples to other monochromatic waves, or as a random phase wave coupling to other random phase waves. An alternative approach involves a random or broadband pump coupling to monochromatic and/or coherent structures in the plasma. This approach can be implemented through the wave-kinetic model. In this model, the incoming pump wave is described by either a bunch (for coherent waves) or a sea (for random phase waves) of quasi-particles. This approach has been applied to both photon acceleration in laser wakefields and drift wave turbulence in magnetized plasma edge configurations. Numerical simulations have been compared to experiments, varying from photon acceleration to drift mode-zonal flow turbulence, and good qualitative correspondences have been found in all cases.

  • 18.
    Vasconez, Christian L.
    et al.
    Escuela Politec Nacl, Dept Fis, Ladron de Guevara E11-253, Quito 170525, Ecuador..
    Perrone, D.
    ASI Italian Space Agcy, Via Politecn Snc, I-00133 Rome, Italy..
    Marino, R.
    Univ Claude Bernard Lyon 1, Lab Mecan Fluides & Acoust, CNRS, Ecole Cent Lyon,INSA Lyon, F-69134 Ecully, France..
    Laveder, D.
    Univ Cote Azur, CNRS, Observ Cote Azur, Lab JL Lagrange, Blvd Observ,CS 34229, F-06304 Nice 4, France..
    Valentini, F.
    Univ Calabria, Dipartimento Fis, I-87036 Arcavacata Di Rende, CS, Italy..
    Servidio, S.
    Univ Calabria, Dipartimento Fis, I-87036 Arcavacata Di Rende, CS, Italy..
    Mininni, P.
    Univ Buenos Aires, Dipartimento Fis, RA-1428 Buenos Aires, DF, Argentina.;Consejo Nacl Invest Cient & Tecn, IFIBA, RA-1428 Buenos Aires, DF, Argentina..
    Sorriso-Valvo, L.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division. CNR, Ist Sci & Tecnol Plasmi ISTP, Via Amendola 122-D, I-70126 Bari, Italy..
    Local and global properties of energy transfer in models of plasma turbulence2021In: Journal of Plasma Physics, ISSN 0022-3778, E-ISSN 1469-7807, Vol. 87, no 1, article id 825870101Article in journal (Refereed)
    Abstract [en]

    The nature of the turbulent energy transfer rate is studied using direct numerical simulations of weakly collisional space plasmas. This is done comparing results obtained from hybrid Vlasov-Maxwell simulations of collisionless plasmas, Hall magnetohydrodynamics and Landau fluid models reproducing low-frequency kinetic effects, such as the Landau damping. In this turbulent scenario, estimates of the local and global scaling properties of different energy channels are obtained using a proxy of the local energy transfer. This approach provides information on the structure of energy fluxes, under the assumption that the turbulent cascade transfers most of the energy that is then dissipated at small scales by various kinetic processes in these kinds of plasmas.

1 - 18 of 18
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