Search Publications
Acceleration of plasma in current sheet during substorm dipolarizations in the Earth's magnetotail: Comparison of different mechanisms
Parkhomenko, Elena I.; Malova, Helmi V.; Grigorenko, Elena E. +6 more
This work is devoted to the investigation of particle acceleration during magnetospheric dipolarizations. A numerical model is presented taking into account the four scenarios of plasma acceleration that can be realized: (A) total dipolarization with characteristic time scales of ≈3 min; (B) single peak value of the normal magnetic component …
A three-dimensional model of spiral null pair to form ion-scale flux ropes in magnetic reconnection region observed by Cluster
Dunlop, Malcolm; He, Jiansen; Xie, Lun +10 more
The magnetic structure and topology of the three-dimensional magnetic reconnection region are significantly dynamic and complex. Small-scale flux ropes and magnetic null points are frequently detected in the reconnection outflow region and diffusion region due to the increased in situ measurements at high temporal cadences. Previous studies have d…
Dust-ion-acoustic modes at comet 67P/Churyumov-Gerasimenko
Chen, Hui; Yang, Weiheng; Liu, Sanqiu
The dynamics of dust-ion-acoustic (DIA) modes at Comet 67P/Churyumov-Gerasimenko, where H2O+ ions with warm and cold electrons as well as dust grains were detected, are investigated within the two-electron-temperature dusty plasmas model by the kinetic theory. In terms of current-driven DIA waves, the bulk electron drift is a…
Formation of dipolarization fronts after current sheet thinning
Xu, Y.; Fu, H. S.; Liu, C. M. +2 more
Dipolarization front (DF)—a sharp boundary separating hot tenuous plasmas from cold dense plasmas—is a key structure responsible for particle acceleration and energy transport in the magnetotail. How such a structure is formed has been unclear so far. Two possible mechanisms suggested in previous studies are magnetic reconnection and spontaneous f…
Beaming electromagnetic (or heat-flux) instabilities from the interplay with the electron temperature anisotropies
Lazar, M.; Poedts, S.; Yoon, P. H. +1 more
In space plasmas, kinetic instabilities are driven by the beaming (drifting) components and/or the temperature anisotropy of charged particles. The heat-flux instabilities are known in the literature as electromagnetic modes destabilized by the electron beams (or strahls) aligned to the interplanetary magnetic field. A new kinetic approach is prop…
The reduction of magnetic reconnection outflow jets to sub-Alfvénic speeds
Haggerty, Colby C.; Shay, Michael A.; Chasapis, Alexandros +5 more
The outflow velocity of jets produced by collisionless magnetic reconnection is shown to be reduced by the ion exhaust temperature in fully kinetic particle in cell simulations and in situ satellite observations. We derive a scaling relationship for the outflow velocity based on the upstream Alfvén speed and the parallel ion exhaust temperature, w…
Fluid simulations of plasma turbulence at ion scales: Comparison with Vlasov-Maxwell simulations
Passot, T.; Zouganelis, I.; Veltri, P. +5 more
Comparisons are presented between a hybrid Vlasov-Maxwell (HVM) simulation of turbulence in a collisionless plasma and fluid reductions. These include Hall-magnetohydrodynamics (HMHD) and Landau fluid (LF) or finite Larmor radius-Landau fluid (FLR-LF) models that retain pressure anisotropy and low-frequency kinetic effects such as Landau damping a…
Particle simulation of electromagnetic emissions from electrostatic instability driven by an electron ring beam on the density gradient
Omura, Yoshiharu; Santolík, Ondřej; Horký, Miroslav
This paper presents the wave mode conversion between electrostatic and electromagnetic waves on the plasma density gradient. We use 2-D electromagnetic code KEMPO2 implemented with the generation of density gradient to simulate such a conversion process. In the dense region, we use ring beam instability to generate electron Bernstein waves and we …
Magnetohydrodynamic waves and the Kelvin-Helmholtz instability at the boundary of plasma mediums
Kozak, L.; Kronberg, E.; Cheremnykh, S. +1 more
It has been theoretically established that shear plasma flows at the boundary of the medium can generate eight MHD modes, of which only one can be unstable due to the development of the Kelvin-Helmholtz instability. It is shown that oblique perturbations propagating at an angle with respect to the velocity vector play a dominant role in the develo…
On the influence of the local maxima of total pressure on the current sheet stability to the kink-like (flapping) mode
Korovinskiy, D. B.; Semenov, V. S.; Erkaev, N. V. +3 more
The stability of the Fadeev-like current sheet with respect to transversally propagating kink-like perturbations (flapping mode) is considered in terms of two-dimensional linear magnetohydrodynamic numerical simulations. It is found that the current sheet is stable when the total pressure minimum is located in the sheet center and unstable when th…