Search Publications
Introduction to special section on Origins and Properties of Kappa Distributions: Statistical Background and Properties of Kappa Distributions in Space Plasmas
Livadiotis, George
Empirical kappa distributions provide a straightforward replacement of the Maxwell distribution for systems out of thermal equilibrium such as space plasmas. Kappa distributions have become increasingly widespread across space physics with the number of relevant publications following, remarkably, an exponential growth rate. However, a breakthroug…
A statistical study of EMIC waves observed by Cluster: 1. Wave properties
André, M.; Klecker, B.; Kistler, L. M. +6 more
Electromagnetic ion cyclotron (EMIC) waves are an important mechanism for particle energization and losses inside the magnetosphere. In order to better understand the effects of these waves on particle dynamics, detailed information about the occurrence rate, wave power, ellipticity, normal angle, energy propagation angle distributions, and local …
The search for a subsurface ocean in Ganymede with Hubble Space Telescope observations of its auroral ovals
Saur, Joachim; Simon, Sven; Neubauer, Fritz M. +11 more
We present a new approach to search for a subsurface ocean within Ganymede through observations and modeling of the dynamics of its auroral ovals. The locations of the auroral ovals oscillate due to Jupiter's time-varying magnetospheric field seen in the rest frame of Ganymede. If an electrically conductive ocean is present, the external time-vary…
How to find magnetic nulls and reconstruct field topology with MMS data?
André, M.; Vaivads, A.; Cao, J. B. +6 more
In this study, we apply a new method—the first-order Taylor expansion (FOTE)—to find magnetic nulls and reconstruct magnetic field topology, in order to use it with the data from the forthcoming MMS mission. We compare this method with the previously used Poincare index (PI), and find that they are generally consistent, except that the PI method c…
Interplanetary coronal mass ejections from MESSENGER orbital observations at Mercury
Lugaz, Noé; Farrugia, Charles J.; Schwadron, Nathan A. +4 more
We use observations from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, in orbit around Mercury, to investigate interplanetary coronal mass ejections (ICMEs) near 0.3 AU. MESSENGER is the first spacecraft since Helios 1 and 2 in the 1980s to make in situ measurements of the interplanetary medium at helioc…
Relation between fine structure of energy spectra for pulsating aurora electrons and frequency spectra of whistler mode chorus waves
Asamura, K.; Santolik, O.; Ebihara, Y. +10 more
We investigate the origin of the fine structure of the energy spectrum of precipitating electrons for the pulsating aurora (PsA) observed by the low-altitude Reimei satellite. The Reimei satellite achieved simultaneous observations of the optical images and precipitating electrons of the PsA from satellite altitude (~620 km) with resolution of 40 …
Evolution of the lower hybrid drift instability at reconnection jet front
André, M.; Vaivads, A.; Khotyaintsev, Yu. V. +3 more
We investigate current-driven modes developing at jet fronts during collisionless reconnection. Initial evolution of the reconnection is simulated using conventional 2-D setup starting from the Harris equilibrium. Three-dimensional PIC calculations are implemented at later stages, when fronts are fully formed. Intense currents and enhanced wave ac…
Field-aligned currents in Saturn's northern nightside magnetosphere: Evidence for interhemispheric current flow associated with planetary period oscillations
Coates, A. J.; Dougherty, M. K.; Alexeev, I. I. +6 more
We investigate the magnetic perturbations associated with field-aligned currents observed on 34 Cassini passes over the premidnight northern auroral region during 2008. These are found to be significantly modulated not only by the northern planetary-period oscillation (PPO) system, similar to the southern currents by the southern PPO system found …
On the origin of magnetosheath plasmoids and their relation to magnetosheath jets
Gunell, H.; Nilsson, H.; Hamrin, M. +4 more
We investigate localized magnetosheath and solar wind density enhancements, associated with clear magnetic field changes, and therefore referred to as magnetosheath/solar wind plasmoids, respectively. Using Cluster data, we show that there are two distinct populations of magnetosheath plasmoids, one associated with a decrease of magnetic field str…
Properties and origin of subproton-scale magnetic holes in the terrestrial plasma sheet
Burgess, D.; Sundberg, T.; Haynes, C. T.
Electron-scale magnetic depressions in the terrestrial plasma sheet are studied using Cluster multispacecraft data. The structures, which have an observed duration of ~5-10 s, are approximately 200-300 km wide in the direction of propagation, and they show an average reduction in the background magnetic field of 10-20%. A majority of the events ar…