Search Publications
The link between shocks, turbulence, and magnetic reconnection in collisionless plasmas
Sibeck, D.; Nykyri, K.; Daughton, W. +11 more
Global hybrid (electron fluid, kinetic ions) and fully kinetic simulations of the magnetosphere have been used to show surprising interconnection between shocks, turbulence, and magnetic reconnection. In particular, collisionless shocks with their reflected ions that can get upstream before retransmission can generate previously unforeseen phenome…
Firehose and Mirror Instabilities in a Collisionless Shearing Plasma
Kunz, Matthew W.; Schekochihin, Alexander A.; Stone, James M.
Hybrid-kinetic numerical simulations of firehose and mirror instabilities in a collisionless plasma are performed in which pressure anisotropy is driven as the magnetic field is changed by a persistent linear shear S. For a decreasing field, it is found that mostly oblique firehose fluctuations grow at ion Larmor scales and saturate with energies …
Circulation of Heavy Ions and Their Dynamical Effects in the Magnetosphere: Recent Observations and Models
Dandouras, Iannis; Malova, Helmi V.; Grigorenko, Elena E. +13 more
Knowledge of the ion composition in the near-Earth's magnetosphere and plasma sheet is essential for the understanding of magnetospheric processes and instabilities. The presence of heavy ions of ionospheric origin in the magnetosphere, in particular oxygen (O+), influences the plasma sheet bulk properties, current sheet (CS) thickness …
Whistler Mode Waves and the Electron Heat Flux in the Solar Wind: Cluster Observations
Maksimovic, M.; Alexandrova, O.; de Conchy, Y. +5 more
The nature of the magnetic field fluctuations in the solar wind between the ion and electron scales is still under debate. Using the Cluster/STAFF instrument, we make a survey of the power spectral density and of the polarization of these fluctuations at frequencies f in [1, 400] Hz, during five years (2001-2005), when Cluster was in the free sola…
Computing the reconnection rate in turbulent kinetic layers by using electron mixing to identify topology
Daughton, W.; Nakamura, T. K. M.; Karimabadi, H. +2 more
Three-dimensional kinetic simulations of magnetic reconnection for parameter regimes relevant to the magnetopause current layer feature the development of turbulence, driven by the magnetic and velocity shear, and dominated by coherent structures including flux ropes, current sheets, and flow vortices. Here, we propose a new approach for computing…
Kelvin Helmholtz Instability in Planetary Magnetospheres
Wing, Simon; Delamere, Peter A.; Johnson, Jay R.
Kelvin-Helmholtz instability plays a particularly important role in plasma transport at magnetospheric boundaries because it can control the development of a turbulent boundary layer, which governs the transport of mass, momentum, and energy across the boundary. Waves generated at the interface can also couple into body modes in the plasma sheet a…
Consequences of geomagnetic activity on energization and loss of radiation belt electrons by oblique chorus waves
Krasnoselskikh, V.; Artemyev, A. V.; Agapitov, O. V. +1 more
Statistics of amplitudes and obliquity of lower band chorus whistler mode waves have been obtained from Cluster measurements in Earth's outer radiation belt and fitted as functions of L, latitude, magnetic local time, and three geomagnetic activity ranges for Dst∈[+10,-80] nT. Very oblique chorus waves have generally a much smaller average intensi…
Kinetic Turbulence in the Terrestrial Magnetosheath: Cluster Observations
Sahraoui, F.; Deng, X. H.; Huang, S. Y. +5 more
We present a first statistical study of subproton- and electron-scale turbulence in the terrestrial magnetosheath using waveform data measured by the Cluster/STAFF search coil magnetometer in the frequency range [1, 180] Hz. It is found that clear spectral breaks exist near the electron scale, which separate two power-law-like frequency bands refe…
Review of Solar Wind Entry into and Transport Within the Plasma Sheet
Escoubet, C. P.; Wing, S.; Lavraud, B. +8 more
The plasma sheet is populated in part by the solar wind plasma. Four solar entry mechanisms are examined: (1) double cusp or double lobe reconnection, (2) Kelvin-Helmholtz Instability (KHI), (3) Kinetic Alfvén waves (KAW), and (4) Impulsive Penetration. These mechanisms can efficiently fill the plasma sheet with cold dense ions during northward in…
Propagation of lower-band whistler-mode waves in the outer Van Allen belt: Systematic analysis of 11 years of multi-component data from the Cluster spacecraft
Santolík, Ondřej; Cornilleau-Wehrlin, Nicole; Kolmašová, Ivana +2 more
Lower-band whistler-mode emissions can influence the dynamics of the outer Van Allen radiation belts. We use 11 years of measurements of the STAFF-SA instruments onboard the four Cluster spacecraft to systematically build maps of wave propagation parameters as a function of position. We determine probability distributions of wave vector angle weig…