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Solar Wind Turbulence and the Role of Ion Instabilities
Bale, S. D.; Alexandrova, O.; Horbury, T. S. +2 more
Solar wind is probably the best laboratory to study turbulence in astrophysical plasmas. In addition to the presence of magnetic field, the differences with neutral fluid isotropic turbulence are: (i) weakness of collisional dissipation and (ii) presence of several characteristic space and time scales. In this paper we discuss observational proper…
In-Situ Observations of Reconnection in Space
Phan, Tai; Paschmann, Götz; Øieroset, Marit
This paper gives an overview of the insights into the magnetic reconnection process obtained by in-situ measurements across current sheets found in planetary magnetospheres and the solar wind. Emphasis is placed on results that might be of interest to the study of reconnection in regions where no in-situ observations are available. These results i…
The Dynamic Quasiperpendicular Shock: Cluster Discoveries
Bale, S. D.; Krasnoselskikh, V.; Walker, S. N. +9 more
The physics of collisionless shocks is a very broad topic which has been studied for more than five decades. However, there are a number of important issues which remain unresolved. The energy repartition amongst particle populations in quasiperpendicular shocks is a multi-scale process related to the spatial and temporal structure of the electrom…
Kinetic Structure of Current Sheets in the Earth Magnetotail
Zelenyi, Lev; Artemyev, Anton
In this paper we present a short review of kinetic models of the thin current sheet and corresponding Cluster observations in the Earth magnetotail. We concentrate mainly on manifestations of non-fluid ion kinetic effects. We discuss the different approaches to model description of the proton component and show that current sheets observed by Clus…
Methods for Characterising Microphysical Processes in Plasmas
Alexandrova, O.; Dudok de Wit, T.; Sorriso-Valvo, L. +2 more
Advanced spectral and statistical data analysis techniques have greatly contributed to shaping our understanding of microphysical processes in plasmas. We review some of the main techniques that allow for characterising fluctuation phenomena in geospace and in laboratory plasma observations. Special emphasis is given to the commonalities between d…
Microphysics of Quasi-parallel Shocks in Collisionless Plasmas
Scholer, M.; Burgess, D.
Shocks in collisionless plasmas require dissipation mechanisms which couple fields and particles at scales much less than the conventional collisional mean free path. For quasi-parallel geometries, where the upstream magnetic field makes a small angle to the shock normal direction, wave-particle coupling produces a broad transition zone with large…
Mechanisms of Spontaneous Reconnection: From Magnetospheric to Fusion Plasma
Zelenyi, Lev; Artemyev, Anton
Very often space plasma is treated as collisionless. We check the validity of this paradigm considering various regimes of tearing mode (spontaneous reconnection) including effects of particle collisions and shear of magnetic field. We briefly describe Pitaevskii's effect of effective modification of collision frequency due to the finite particle …
Microphysics in Astrophysical Plasmas
Schwartz, Steven J.; Zweibel, Ellen G.; Goldman, Martin
Although macroscale features dominate astrophysical images and energetics, the physics is controlled through microscale transport processes (conduction, diffusion) that mediate the flow of mass, momentum, energy, and charge. These microphysical processes manifest themselves in key (all) boundary layers and also operate within the body of the plasm…