The magnetospheric response to the solar wind is nonlinear. Information theoretical tools are able to characterize the nonlinearities in the system. We show that nonlinear significance of D_st peaks at lags of 3–12 hours which can be attributed to VB_s, which also exhibits similar behavior. However, the nonlinear significance that peaks at lags of 25, 50, and 90 hours can be attributed to internal dynamics, which may be related to the relaxation of the ring current.

GREEN (Global Radiation Earth ENvironment) is a new model providing particle fluxes at any location in the radiation belts, for energy between 1 keV and 10 MeV for electrons and between 1 keV and 800 MeV for protons. This model is composed of global models (AE8 and AP8, and SPM) and local models (SLOT model, OZONE and IGE-2006 for electrons; OPAL and IGP for protons).

We proposed a new method to determine the scale height of water vapor, which will improve the quality of vertical constraints. Then, the smoothing factor in the horizontal constraint was determined based on ERA-Interim products. The evaluation results show that the water vapor density quality obtained by the optimized technique is 13.8 % better below 3.8 km and 8.1 % better above 3.8 km than that obtained by the traditional technique.

The novelty of this paper lies in the fact that it addresses the thermosphere–ionosphere coupling in a midlatitude site in north Africa. We have used Fabry–Perot measurements of thermospheric winds and wide-angle camera detection of ionospheric structures at an altitude of about 250 km. We have also used GPS data to extract the TEC over the studied area. We have focused our study on the 27 February geomagnetic storm.

Based on comparisons of meteor radar measurements with HAMMONIA model simulations, we show that the differences exhibited by the semidiurnal solar tide (S2) observed at middle and high latitudes of the Northern Hemisphere between equinox times are mainly due to distinct behaviors of the migrating semidiurnal (SW2) and the non-migrating westward-propagating wave number 1 semidiurnal (SW1) tidal components.

By induction, ocean tides generate electromagnetic signals. Since the launch of magnetometer satellite missions, these signals are increasingly used to infer electromagnetic properties of the Earth. In many of these inversions, ocean tide models are used to estimate oceanic tidal electromagnetic signals which are generated via electromagnetic induction. This study's goal is to provide tide model errors for electromagnetic inversion studies.

The physics of the magnetic mirror mode in its final state of saturation, the thermodynamic equilibrium, is re-examined to demonstrate that the mirror mode is the classical analogue of a superconducting effect in an anisotropic-pressure space plasma. Three different spatial correlation scales are identified which control the behaviour of its evolution into large-amplitude chains of mirror bubbles.

The Earth's magnetic field is shaped by the solar wind. On the dayside the field is compressed and on the nightside it is stretched as a long tail. The tail has been observed to occasionally undergo flapping motions, but the origin of these motions is not understood. We study the flapping using a numerical simulation of the near-Earth space. We present a possible explanation for how the flapping could be initiated by a passing disturbance and then maintained as a standing wave.

This paper proposes an optimal tropospheric tomography approach with the support of an auxiliary area, which has the ability to use the signals crossing out from the top boundary of the tomographic area. Additionally, the top height of the tomography body is determined based on the average water vapour distribution derived from the COSMIC data. The compared result reveals the superiority of the proposed method when compared to the conventional method.

Does the reformation of perpendicular shocks really exist in the real space plasma? The reformation was first reported in numerical simulations in one spatial dimension, and then was indicated by in situ observation by the Cluster spacecraft. The present study aimed to answer this question by performing advanced numerical simulations in two spatial dimensions. The present study suggests that the reformation exists under a limited plasma condition.

At the bow shock the solar wind is slowed down in front of Earth's magnetosphere. This is accompanied by a gain in strength of the magnetic field, which implies that the bow shock carries electric currents. We present the a comprehensive statistical study of bow shock currents making use of multi-point data collected by Cluster spacecraft. We find that the currents depend on the shock geometry and the interplanetary magnetic field and are in good accordance with theory and simulation results.

We use the Vlasiator code to study the characteristics of transient structures that exist in the Earth's foreshock, i.e. upstream of the bow shock. The structures are cavitons and spontaneous hot flow anomalies (SHFAs). These transients can interact with the bow shock. We study the changes the shock suffers via this interaction. We also investigate ion distributions associated with the cavitons and SHFAs. A very important result is that the arrival of multiple SHFAs results in shock erosion.

We used sounding rockets to obtain four high-resolution temperature profiles in the mesosphere over a limited area. We found consistent deep isothermal and adiabatic layers, but variable and finely structured turbulence preferentially in the lower stable mesosphere. Accompanying tracer releases showed horizontal winds in the lower thermosphere with extreme shears and 200 m  s⁻¹ winds under moderately disturbed geomagnetic conditions, and convection-like structures just below the mesopause.

This paper describes an algorithm that automatically detects vortices around the Earth's magnetosphere using the velocity field from simulated data. It also describes how the tool can be used to analyze further properties of the vortices including the velocity changes within their motion across the magnetosheath. Vortices developed at the magnetopause boundary contribute to the process of mass, momentum and energy transfer from the solar wind into the Earth's magnetosphere.

The position of the external boundary of the outer electron radiation belt (ORB), relative to the auroral oval's position, is hard to determine. It was done using simultaneous measurements of energetic and auroral electrons onboard METEOR-M1. Our analysis shows that the ORB boundary is often located inside the auroral oval and that the number of such events increases with growing geomagnetic activity. These results are relevant to our understanding of the topology of the geomagnetic field.

A record has been found of an "aurora" observed on 27 October 1856 in the Philippines, practically at the magnetic equator. An analysis of this report indicates that it could belong to a "sporadic aurora" because of low magnetic activity at that time. We provide a possible physical mechanism that could explain the appearance of this sporadic, low-latitude aurora, according to the analyses on the observational report and magnetic observations at that time.