Search Publications
Local Kinetic Effects in Two-Dimensional Plasma Turbulence
Veltri, P.; Califano, F.; Servidio, S. +1 more
Using direct numerical simulations of a hybrid Vlasov-Maxwell model, kinetic processes are investigated in a two-dimensional turbulent plasma. In the turbulent regime, kinetic effects manifest through a deformation of the ion distribution function. These patterns of non-Maxwellian features are concentrated in space nearby regions of strong magneti…
Intermittent Dissipation at Kinetic Scales in Collisionless Plasma Turbulence
Matthaeus, W. H.; Chapman, S. C.; Daughton, W. +6 more
High resolution kinetic simulations of collisionless plasma driven by shear show the development of turbulence characterized by dynamic coherent sheetlike current density structures spanning a range of scales down to electron scales. We present evidence that these structures are sites for heating and dissipation, and that stronger current structur…
Detection of Small-Scale Structures in the Dissipation Regime of Solar-Wind Turbulence
Perri, S.; Sahraoui, F.; Goldstein, M. L. +1 more
Recent observations of the solar wind have pointed out the existence of a cascade of magnetic energy from the scale of the proton Larmor radius ρp down to the electron Larmor radius ρe scale. In this Letter we study the spatial properties of magnetic field fluctuations in the solar wind and find that at small scales the magne…
Particle Acceleration in Turbulence and Weakly Stochastic Reconnection
Lazarian, A.; Kowal, Grzegorz; de Gouveia Dal Pino, Elisabete M.
In this Letter we analyze the energy distribution evolution of test particles injected in three dimensional (3D) magnetohydrodynamic (MHD) simulations of different magnetic reconnection configurations. When considering a single Sweet-Parker topology, the particles accelerate predominantly through a first-order Fermi process, as predicted in and de…
Lower Hybrid Drift Waves: Space Observations
Khotyaintsev, Yuri V.; Vaivads, Andris; André, Mats +1 more
Lower hybrid drift waves (LHDWs) are commonly observed at plasma boundaries in space and laboratory, often having the strongest measured electric fields within these regions. We use data from two of the Cluster satellites (C3 and C4) located in Earth’s magnetotail and separated by a distance of the order of the electron gyroscale. These conditions…
Secondary Magnetic Islands Generated by the Kelvin-Helmholtz Instability in a Reconnecting Current Sheet
Drake, J. F.; Swisdak, M.; Fermo, R. L.
Magnetic islands or flux ropes produced by magnetic reconnection have been observed on the magnetopause, in the magnetotail, and in coronal current sheets. Particle-in-cell simulations of magnetic reconnection with a guide field produce elongated electron current layers that spontaneously produce secondary islands. Here, we explore the seed mechan…
Spontaneous Chiral Symmetry Breaking of Hall Magnetohydrodynamic Turbulence
Galtier, Sébastien; Meyrand, Romain
Hall magnetohydrodynamics (MHD) is investigated through three-dimensional direct numerical simulations. We show that the Hall effect induces a spontaneous chiral symmetry breaking of the turbulent dynamics. The normalized magnetic polarization is introduced to separate the right- (R) and left-handed (L) fluctuations. A classical k-7/3 s…
Dispersive Nature of High Mach Number Collisionless Plasma Shocks: Poynting Flux of Oblique Whistler Waves
Bale, S. D.; Krasnoselskikh, V.; Schwartz, S. J. +3 more
Whistler wave trains are observed in the foot region of high Mach number quasiperpendicular shocks. The waves are oblique with respect to the ambient magnetic field as well as the shock normal. The Poynting flux of the waves is directed upstream in the shock normal frame starting from the ramp of the shock. This suggests that the waves are an inte…
Entropy Generation across Earth's Collisionless Bow Shock
Dandouras, I.; Cao, J. B.; Parks, G. K. +9 more
Earth’s bow shock is a collisionless shock wave but entropy has never been directly measured across it. The plasma experiments on Cluster and Double Star measure 3D plasma distributions upstream and downstream of the bow shock allowing calculation of Boltzmann’s entropy function H and his famous H theorem, dH/dt≤0. The collisionless Boltzmann (Vla…
Observations of Ionospheric Electron Beams in the Plasma Sheet
Parks, G. K.; Fu, S. Y.; Pu, Z. Y. +3 more
Electrons streaming along the magnetic field direction are frequently observed in the plasma sheet of Earth’s geomagnetic tail. The impact of these field-aligned electrons on the dynamics of the geomagnetic tail is however not well understood. Here we report the first detection of field-aligned electrons with fluxes increasing at ∼1keV forming a “…