Search Publications
Electron Acceleration by Dipolarization Fronts and Magnetic Reconnection: A Quantitative Comparison
Xu, Y.; Fu, H. S.; Liu, C. M. +1 more
Suprathermal electrons with energy from tens to hundreds of keV are frequently observed in the Earth's magnetotail. The generation of such electrons is typically attributed to magnetic reconnection, dipolarization fronts (DFs), or flux transport. However, which of these contributes more to this generation remains unclear. In this study, we quantit…
Dual Phase-space Cascades in 3D Hybrid-Vlasov-Maxwell Turbulence
Califano, F.; Cerri, S. S.; Kunz, M. W.
To explain energy dissipation via turbulence in collisionless, magnetized plasmas, the existence of a dual real- and velocity-space cascade of ion-entropy fluctuations below the ion gyroradius has been proposed. Such a dual cascade, predicted by the gyrokinetic theory, has previously been observed in gyrokinetic simulations of two-dimensional, ele…
Incompressive Energy Transfer in the Earth’s Magnetosheath: Magnetospheric Multiscale Observations
Russell, C. T.; Torbert, R. B.; Matthaeus, W. H. +14 more
Using observational data from the Magnetospheric Multiscale mission in the Earth’s magnetosheath, we estimate the energy cascade rate at three ranges of length scale, employing a single data interval, using different techniques within the framework of incompressible magnetohydrodynamic (MHD) turbulence. At the energy-containing scale, the energy b…
Magnetic Nulls in the Reconnection Driven by Turbulence
Dunlop, M. W.; Wang, Z.; Fu, H. S. +5 more
For the first time, we use spacecraft measurements to investigate the magnetic nulls in a reconnection event driven by turbulence in the magnetosheath. We particularly focus on the relation between magnetic-null topologies and currents, which can be decomposed into a component perpendicular to spine ({J}\perp ) and a component parallel …
Detection of Magnetic Nulls around Reconnection Fronts
Divin, A.; Xu, Y.; Fu, H. S. +2 more
Magnetic nulls, where magnetic-field strength becomes zero, play a crucial role in energy conversion and particle acceleration during magnetic reconnection. Recent simulations have suggested that reconnection fronts (RFs) inside the reconnection jet can host magnetic nulls. However, observational evidence for the RF-associated magnetic nulls remai…
Dynamics of Intense Currents in the Solar Wind
Zelenyi, Lev M.; Angelopoulos, Vassilis; Artemyev, Anton V. +3 more
Transient currents in the solar wind are carried by various magnetic field discontinuities that contribute significantly to the magnetic field fluctuation spectrum. Internal instabilities and dynamics of these discontinuities are believed to be responsible for magnetic field energy dissipation and corresponding charged particle acceleration and he…
Betatron Cooling of Suprathermal Electrons in the Terrestrial Magnetotail
Xu, Y.; Liu, Y. Y.; Liu, C. M. +1 more
The cigar distribution of suprathermal electrons (40-200 keV), showing electron pitch angles primarily in the parallel and anti-parallel directions, has been frequently observed in the terrestrial magnetotail. The formation of such a distribution is typically attributed to Fermi acceleration, betatron cooling, or a combination of these. To date, F…
Properties of Decaying Plasma Turbulence at Subproton Scales
Servidio, Sergio; Lapenta, Giovanni; Primavera, Leonardo +2 more
We study the properties of plasma turbulence at subproton scales using kinetic electromagnetic three-dimensional simulations with nonidentical initial conditions. Particle-in-cell modeling of the Taylor-Green vortex has been performed, starting from three different magnetic field configurations. All simulations expose very similar energy evolution…
Effect of Upstream ULF Waves on the Energetic Ion Diffusion at the Earth’s Foreshock. II. Observations
Dandouras, Iannis; Matsukiyo, Shuichi; Kis, Arpad +5 more
This study reports observations of energetic ions upstream of the Earth’s quasi-parallel bow shock by Cluster at times when interspacecraft separation distances were large. We analyze two individual upstream ion events during high solar wind velocity conditions to compare the spatial evolution of partial energetic ion densities in front of the Ear…
3D Electric Waveforms of Solar Wind Turbulence
Goetz, K.; Kellogg, P. J.; Monson, S. J.
Electric fields provide the major coupling between the turbulence of the solar wind and particles. A large part of the turbulent spectrum of fluctuations in the solar wind is thought to be kinetic Alfvén waves; however, whistlers have recently been found to be important. In this article, we attempt to determine the mode identification of individua…