Search Publications
Dissipation in Turbulent Plasma due to Reconnection in Thin Current Sheets
Retinò, Alessandro; Sundkvist, David; Vaivads, Andris +1 more
We present in situ measurements in a space plasma showing that thin current sheets the size of an ion inertial length exist and are abundant in strong and intermittent plasma turbulence. Many of these current sheets exhibit the microphysical signatures of reconnection. The spatial scale where intermittency occurs corresponds to the observed struct…
Evidence for an Elongated (>60 Ion Skin Depths) Electron Diffusion Region during Fast Magnetic Reconnection
Eastwood, J. P.; Phan, T. D.; Mozer, F. S. +2 more
Observations of an extremely elongated electron diffusion region occurring during fast reconnection are presented. Cluster spacecraft in situ observations of an expanding reconnection exhaust reveal a broad current layer (∼10 ion skin depths thick) supporting the reversal of the reconnecting magnetic field together with an intense current embedded…
Mode Conversion and Anomalous Transport in Kelvin-Helmholtz Vortices and Kinetic Alfvén Waves at the Earth's Magnetopause
Acuna, M.; Fujimoto, M.; Reme, H. +5 more
Observations at the Earth’s magnetopause identify mode conversion from surface to kinetic Alfvén waves at the Alfvén resonance. Kinetic Alfvén waves radiate into the magnetosphere from the resonance with parallel scales up to the order of the geomagnetic field-line length and spectral energy densities obeying a k⊥-2.4 power l…
Magnetic Double-Gradient Instability and Flapping Waves in a Current Sheet
Semenov, V. S.; Erkaev, N. V.; Biernat, H. K.
A new kind of magnetohydrodynamic instability and waves are analyzed for a current sheet in the presence of a small normal magnetic field component varying along the sheet. These waves and instability are related to the existence of two gradients of the tangential (Bτ) and normal (Bn) magnetic field components along the norma…
Spontaneous Generation of Self-Organized Solitary Wave Structures at Earth's Magnetopause
Davies, J. A.; Vaivads, A.; Dunlop, M. W. +5 more
Spontaneous formation of solitary wave structures has been observed in Earth’s magnetopause, and is shown to be caused by the breakup of a zonal flow by the action of drift wave turbulence. Here we show matched observations and modeling of coherent, large-scale solitary electrostatic structures, generated during the interaction of short-scale drif…
Solitary Electromagnetic Pulses Detected with Super-Alfvénic Flows in Earth's Geomagnetic Tail
Dandouras, I.; Lucek, E.; Rème, H. +11 more
Solitary nonlinear (δB/B≫1) electromagnetic pulses have been detected in Earth’s geomagnetic tail accompanying plasmas flowing at super-Alfvénic speeds. The pulses in the current sheet had durations of ∼5s, were left-hand circularly polarized, and had phase speeds of approximately the Alfvén speed in the plasma frame. These pulses were associated …
Stringent Constraint on Galactic Positron Production
Beacom, John F.; Yüksel, Hasan
The intense 0.511 MeV gamma-ray line emission from the Galactic Center observed by INTEGRAL requires a large annihilation rate of nonrelativistic positrons. If these positrons are injected at even mildly relativistic energies, higher-energy gamma rays will also be produced. We calculate the gamma-ray spectrum due to inflight annihilation and compa…
Strategy for Searching for a Dark Matter Sterile Neutrino
Neronov, A.; Boyarsky, A.; Ruchayskiy, O. +2 more
We propose a strategy for how to look for dark matter particles possessing a radiative decay channel and derive constraints on their parameters from observations of x rays from our own Galaxy and its dwarf satellites. When applied to sterile neutrinos in the keV mass range this approach gives a significant improvement to restrictions on neutrino p…
Anisotropic Turbulent Spectra in the Terrestrial Magnetosheath as Seen by the Cluster Spacecraft
Balogh, A.; Belmont, G.; Sahraoui, F. +3 more
Here we report the first three-dimensional spatial spectrum of the low frequency magnetic turbulence obtained from the four Cluster spacecraft in the terrestrial magnetosheath close to the magnetopause. We show that the turbulence is compressible and dominated by mirror structures, its energy is injected at a large scale kρ∼0.3 (l∼2000 km) via a m…
Formation of Inner Structure of a Reconnection Separatrix Region
Nilsson, H.; André, M.; Vaivads, A. +3 more
We present multipoint spacecraft observations at the dayside magnetopause of a magnetic reconnection separatrix region. This region separates two plasmas with significantly different temperatures and densities, at a large distance from the X line. We identify which terms in the generalized Ohm’s law balance the observed electric field throughout t…