Search Publications
Multispacecraft observations of the electron current sheet, neighboring magnetic islands, and electron acceleration during magnetotail reconnectiona)
Fazakerley, Andrew; Khotyaintsev, Yuri; Lefebvre, Bertrand +9 more
Open questions concerning structures and dynamics of diffusion regions and electron acceleration in collisionless magnetic reconnection are addressed based on data from the four-spacecraft mission Cluster and particle-in-cell simulations. Using time series of electron distribution functions measured by the four spacecraft, distinct electron region…
Applications of the wave kinetic approach: From laser wakefields to drift wave turbulencea)
Davies, J. A.; Vaivads, A.; Dunlop, M. W. +8 more
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…
Numerical experiments on plasmoids entering a transverse magnetic field
Gunell, H.; Nilsson, H.; Brenning, N. +3 more
Plasma from the Earth's magnetosheath has previously been observed inside the magnetosphere. Inhomogeneities in the magnetosheath plasma, here called plasmoids, can impact the magnetopause and doing so set up a polarizing field that allows it to penetrate the magnetopause and enter the magnetosphere. A set of simulations of plasmoids with differen…
Nonlinear gyrokinetic theory for steady-state mirror mode magnetic structures
Jovanović, D.; Shukla, P. K.
The analytic study of the saturated state of the mirror instability is presented. The perpendicular ion momentum is described by the hydrodynamic equations, with the finite Larmor radius corrections found from the collisionless stress tensor, while the ion density, the parallel flow, and the pressure are calculated using the gyrokinetic descriptio…
Kinetic Alfvén waves turbulence in the Earth's magnetosphere
Sharma, R. P.; Kumar, Sachin
The numerical simulations of the model equation governing the nonlinear dynamics of kinetic Alfvén waves in the intermediate-β plasmas are performed. When the nonlinearity arises due to the ponderomotive force driven density perturbations of kinetic Alfvén waves, the model equation turns out to be a modified nonlinear Schrödinger equation. This ha…
Kinetic theory for the ion humps at the foot of the Earth's bow shock
Krasnoselskikh, V. V.; Jovanović, D.
The nonlinear kinetic theory is presented for the ion acoustic perturbations at the foot of the Earth's quasiperpendicular bow shock, that is characterized by weakly magnetized electrons and unmagnetized ions. The streaming ions, due to the reflection of the solar wind ions from the shock, provide the free energy source for the linear instability …
Drift-Alfvén vortices at the ion Larmor radius scale
Krasnoselskikh, V. V.; Pokhotelov, O. A.; Onishchenko, O. G.
The theory of nonlinear drift-Alfvén waves with the spatial scales comparable to the ion Larmor radius is developed. It is shown that the set of equations describing the nonlinear dynamics of drift-Alfvén waves in a quasistationary regime admits a solution in the form of a solitary dipole vortex. The vortex structures propagating perpendicular to …
Transport of transient solar wind particles in Earth's cusps
Dandouras, I.; Rème, H.; Parks, G. K. +7 more
An important problem in space physics still not understood well is how the solar wind enters the Earth's magnetosphere. Evidence is presented that transient solar wind particles produced by solar disturbances can appear in the Earth's mid-altitude (~5 RE geocentric) cusps with densities nearly equal to those in the magnetosheath. That t…
Statistics of beam-driven waves in plasmas with ambient fluctuations: Reduced-parameter approach
Robinson, P. A.; Tyshetskiy, Yu.; Cairns, I. H.
A reduced-parameter (RP) model of quasilinear wave-plasma interactions is used to analyze statistical properties of beam-driven waves in plasmas with ambient density fluctuations. The probability distribution of wave energies in such a system is shown to have a relatively narrow peak just above the thermal wave level, and a power-law tail at high …
Parametric instabilities of parallel propagating incoherent Alfvén waves in a finite ion beta plasma
Nariyuki, Y.; Hada, T.; Tsubouchi, K.
Large amplitude, low-frequency Alfvén waves constitute one of the most essential elements of magnetohydrodynamic (MHD) turbulence in the fast solar wind. Due to small collisionless dissipation rates, the waves can propagate long distances and efficiently convey such macroscopic quantities as momentum, energy, and helicity. Since loading of such qu…