The density distribution of ice particles and electrons near the boundary of the polar mesosphere summer echo (PMSE) region is studied. The results show that when the radius distribution function of the condensation nucleus is a Gaussian type, for a certain range of the condensation core radius, sharp peaks with a meter scale appear in the density profiles of ice particles and electrons. These small-scale structures of electron density may be one of the causes of the PMSE phenomenon.

We present the magnetic local time (MLT) distribution of energetic particle precipitation into the ionosphere in combination with different substorm activities. In the long term average substorms may increase the night-sector flux by factor 2–4 and eventually reduce the day-time flux. The MLT flux differences themselves may even reach 2 orders of magnitude independently of substorm activity level. Since precipitating particles impact the ozone chemistry, this may have atmospheric implications.

The Antarctic ozone hole (AOH) directly influences the Antarctic region, where its levels can reach values below 220 DU. The temporary depletion of ozone in Antarctica generally occurs between the beginning and middle of August, during the austral spring, and extends to November, when a temporary reduction in ozone content is observed in a large region over Antarctica. However, masses of ozone-depleted air can break away from the ozone hole and reach mid-latitude regions.

Receiver and satellite differential code biases (DCBs) are one of the main error sources in estimating precise global ionosphere maps (GIMs) from Global Positioning System (GPS) data. This paper introduces a mathematical model for estimating satellite and receiver DCBs from a GPS network written in the MATLAB environment. Our code was tested and compared with Ionosphere Associated Analysis Centers (IAAC) and other researchers' code results. The results show an improvement for estimated DCBs.

In order to validate the CSES ionospheric RO data, ionospheric peak values, peak heights and electron density profiles observed by CSES are compared with the corresponding COSMIC RO measurements obtained from 12 February 2018, to 31 March 2019. The results show the two sets are in good agreement, and CSES ionospheric RO data are available for ionosphere-related studies considering the extensive validation and application of COSMIC RO data.

For the first time, the climatology of intermediate descending layers (~150 km) over Brazilian equatorial and low-latitude regions during the extreme solar minimum period of 2009 was investigated. The results are interesting and innovative. For this analysis we used data of height and top frequency of intermediate layers collected from a digisonde located at São Luis and Cachoreira Paulista.

Atmospheric drag due to mass density distribution, particularly during storm-time, is of great importance for low Earth orbit precise orbit determination, and for the understanding of magnetosphere–ionosphere–thermosphere phenomena. In this paper, we investigate solar cycle, seasonal, and hemispheric asymmetry dependencies of thermospheric mass density disturbances due to magnetospheric forcing, from 10-year (2003–2013) continuous time series of GRACE estimates.

The mirror mode starts as a zero-frequency ion fluid instability and saturates quasi-linearly at very low magnetic level, while forming extended magnetic bubbles. These trap the adiabatically bouncing electron component which forms pairs near the mirror points. The large pair anisotropy causes further growth beyond quasilinear level. Including pressure equilibrium gives and estimate of the required pair density.

Our numerical simulation shows that the drag due to the dissipation and/or breaking of the gravity wave plays an important role in the general circulation in the thermosphere. This means that the parameterization for the gravity wave drag is necessary for numerical simulation in the thermosphere.

We analyzed the forcing mechanisms of the migrating terdiurnal solar tide in the middle atmosphere, focusing the impact on the zonal mean circulation. We show that the primary solar forcing is the most dominant one but secondary wave–wave interactions also contribute in the lower thermosphere region. We further demonstrate that small-scale gravity waves can strongly and irregularly influence the amplitude of the terdiurnal tide as well as the background circulation in the thermosphere.

Previous studies show that the ring current (RC) and field-aligned currents (FACs) are the dominant currents in the inner magnetosphere. However, through two large storm events observed by Cluster, we find new strong southward and northward currents in the latitudinal region from 10° N to 30° N. Theoretical analysis indicates that these currents originated from the fluctuation of magnetic field lines during strong geomagnetic storms.

The wavelet transform was employed in nine HILDCAA events for intervals in which the Cluster crossed the magnetotail in order to identify the most energetic periods of these events in the magnetotail. It was seen that 76 % of the periods identified are ≤4 h. Using the cross wavelet analysis technique between B_z–IMF components and the B_x geomagnetic components, it was identified that the coupling of energy is stronger in periods between 2 and 4 h, which are typical substorm periods.