Search Publications

Substorm Current Wedge Revisited

Lester, M.; Nakamura, R.; McPherron, R. L. +7 more

Almost 40 years ago the concept of the substorm current wedge was developed to explain the magnetic signatures observed on the ground and in geosynchronous orbit during substorm expansion. In the ensuing decades new observations, including radar and low-altitude spacecraft, MHD simulations, and theoretical considerations have tremendously advanced…

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…

Dissipation and heating in solar wind turbulence: from the macro to the micro and back again

Chapman, S. C.; Osman, K. T.; Kiyani, K. H.

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 …

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…

Thin Current Sheets and Associated Electron Heating in Turbulent Space Plasma

Vaivads, A.; Sahraoui, F.; Khotyaintsev, Yu. V. +6 more

Intermittent structures, such as thin current sheets, are abundant in turbulent plasmas. Numerical simulations indicate that such current sheets are important sites of energy dissipation and particle heating occurring at kinetic scales. However, direct evidence of dissipation and associated heating within current sheets is scarce. Here, we show a …

Observations of discrete harmonics emerging from equatorial noise

Dandouras, Iannis; Walker, Simon N.; Balikhin, Michael A. +7 more

A number of modes of oscillations of particles and fields can exist in space plasmas. Since the early 1970s, space missions have observed noise-like plasma waves near the geomagnetic equator known as `equatorial noise'. Several theories were suggested, but clear observational evidence supported by realistic modelling has not been provided. Here we…

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 …

Double layer electric fields aiding the production of energetic flat-top distributions and superthermal electrons within magnetic reconnection exhausts

Borg, A. L.; Egedal, J.; Daughton, W. +1 more

Using a kinetic simulation of magnetic reconnection, it was recently shown that magnetic-field-aligned electric fields (E_∥) can be present over large spatial scales in reconnection exhausts. The largest values of E_∥ are observed within double layers. The existence of double layers in the Earth's magnetosphere is well document…

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…