Search Publications
Super-efficient Electron Acceleration by an Isolated Magnetic Reconnection
Vaivads, A.; Xu, Y.; Fu, H. S. +1 more
Magnetic reconnection—the process typically lasting for a few seconds in space—is able to accelerate electrons. However, the efficiency of the acceleration during such a short period is still a puzzle. Previous analyses, based on spacecraft measurements in the Earth’s magnetotail, indicate that magnetic reconnection can enhance electron fluxes up …
Hybrid-kinetic Simulations of Ion Heating in Alfvénic Turbulence
Quataert, Eliot; Chandran, Benjamin D. G.; Kunz, Matthew W. +1 more
We present three-dimensional, hybrid-kinetic numerical simulations of driven Alfvén-wave turbulence of relevance to the collisionless near-Earth solar wind. Special attention is paid to the spectral transition that occurs near the ion-Larmor scale and to the origins of preferential perpendicular ion heating and of nonthermal wings in the parallel …
Whistler Fan Instability Driven by Strahl Electrons in the Solar Wind
Bale, S. D.; Krasnoselskikh, V.; Mozer, F. S. +3 more
We present a theoretical analysis of electron heat flux inhibition in the solar wind when a significant portion of the heat flux is carried by strahl electrons. We adopt core-strahl velocity distribution functions typical for the solar wind at 0.3-4 au to demonstrate that strahl electrons are capable of generating highly oblique whistler waves at …
Particle-in-cell Simulations of Firehose Instability Driven by Bi-Kappa Electrons
Lazar, M.; Poedts, S.; Viñas, A. F. +4 more
We report the first results from particle-in-cell simulations of the fast-growing aperiodic electron firehose instability driven by the anisotropic bi-Kappa distributed electrons. Such electrons characterize space plasmas, e.g., solar wind and planetary magnetospheres. Predictions made by the linear theory for full wave-frequency and wave-vector s…
Anchor Point of Electron Acceleration around Dipolarization Fronts in Space Plasmas
Fu, H. S.; Liu, C. M.
An anchor point, which is an energy threshold above which electrons are accelerated and below which electrons are decelerated, has recently been reported within the dipolarizing flux bundles behind dipolarization fronts (DFs) both in observations and simulations. However, what determines this point and how it is formed remain unclear. In this stud…
First Observations of Irregular Surface of Interplanetary Shocks at Ion Scales by Cluster
Kajdič, Primož; Blanco-Cano, Xóchitl; Burgess, David +2 more
We present the first observational evidence of the irregular surface of interplanetary (IP) shocks by using multispacecraft observations of the Cluster mission. In total we discuss observations of four IP shocks that exhibit moderate Alfvénic Mach numbers (M A ≤ 6.5). Three of them are high-β shocks with upstream β = 2.2-3.7. During the…
Single-spacecraft Identification of Flux Tubes and Current Sheets in the Solar Wind
Servidio, Sergio; Pecora, Francesco; Greco, Antonella +3 more
A novel technique is presented for describing and visualizing the local topology of the magnetic field using single-spacecraft data in the solar wind. The approach merges two established techniques: the Grad-Shafranov (GS) reconstruction method, which provides a plausible regional two-dimensional magnetic field surrounding the spacecraft trajector…
Energetic Electron Acceleration in Unconfined Reconnection Jets
Xu, Y.; Zhang, Y.; Chen, G. +5 more
Magnetic reconnection in astronomical objects such as solar corona and the Earth’s magnetotail theoretically produces a fast jet toward the object (known as a confined jet as it connects to the object through magnetic field lines) and a fast jet departing the object (known as an unconfined jet as it propagates freely in space). So far, energetic e…
Testing of the Taylor Frozen-in-flow Hypothesis at Electron Scales in the Solar Wind Turbulence
Sahraoui, F.; Huang, S. Y.
In single-spacecraft observations the Taylor frozen-in-flow hypothesis is usually used to infer wavenumber spectra of turbulence from the frequency ones. While this hypothesis can be valid at MHD scales in the solar wind because of the small phase speeds of the fluctuations in comparison with the solar wind flow speed, its validity at electron sca…
Statistics on the Magnetosheath Properties Related to Magnetopause Magnetic Reconnection
Zhang, Hui; Liu, Libo; Wan, Weixing +5 more
Magnetosheath properties, particularly those related to magnetopause magnetic reconnection (MR), are investigated in this study. (1) Asymmetries are found to exist in the distributions of plasma and magnetic field parameters in the magnetosheath. These asymmetries are related to the interplanetary magnetic field (IMF) orientation, and they are pro…