In a magnetic field reversal, the guiding center may not be valid due to large variation of the magnetic field on the length scale of the particle gyro-radius. Although they do not execute regular helical motion and temporarily meander inside the field reversal, quasi-adiabatic particles exit this reversal with a magnetic moment nearly identical to that at entry. We show that this behavior, which is a steady-state concept, can persist during dipolarization despite the induced electric field.

In this paper, we analyze the total ozone column over the Southern Space Observatory, Brazil, between 1992 and 2014 by Brewer spectrometer and TOMS and OMI satellite instruments, finding good agreement between the two. In addition, the seasonal TOC variation is dominated by an annual cycle, and the Quasi-Biennial Oscillation modulation was the main mode of interannual variability and in opposite phase to the total ozone column anomaly time series.

The electrical inductions within the Earth surface due to geomagnetic field variations were examined. For that purpose the records of the geomagnetic and geo-electric field variations observed in West Africa were used. We have found that the geomagnetic field brisk variations induce non-negligible geo-electric field variations at low latitudes. This result implies a possible intense geomagnetically induced current flow in the vicinity of the equatorial electrojet influence area.

Before many catastrophic phenomena such as earthquakes, sound is generated at a very low frequency. It is already established that it can disturb the upper layer of the atmosphere – the ionosphere. Control of disasters' precursors is important. Using the unique, powerful sound generator, whose loudness is comparable to an ascending jet, we have constructed the theory and conducted a series of experiments trying to model acoustic action of disasters on the ionosphere.

Observations during periods when the solar wind has a speed < 425 km s⁻¹ show that it is not uncommon to find no strahl present in the data. The research was done in response to observations and was performed through a detailed study of the electron velocity distribution functions. The conclusion arrived at is that the absence of the strahl appears to occur within individual flux tubes, which may indicate that the source lies in the solar corona where the strahl is formed.

A troposphere tomographic method has been proposed considering the signal rays penetrating from the side of the area of interest. Given the method above needs the establishment of a unit scale factor model using the radiosonde data at only one location in the research area, an improved approach is proposed by considering the reasonability of modelling data and the diversity of the modelling parameters for building a more accurate unit scale factor model.

We present the first statistical results of vertical wind fluctuation spectra, which revealed a very shallow spectral structure, with mean slopes of −0.58 and −0.23 in the troposphere and lower stratosphere, respectively. No existing spectral theories can comprehensively explain the observed three-dimensional wind spectra, indicating that the spectral features of atmospheric fluctuations are far from fully understood.

Vector magnetic field instruments mounted on spacecraft require precise in-flight calibration of the offsets of all three axes, i.e., the output in vanishing ambient field. While calibration of the spin plane offsets is trivial, we apply a new technique for determining the spin axis offset, not relying on solar wind data but on magnetosheath encounters. This technique is successfully applied to the satellites of the THEMIS mission to update the calibration parameters of the complete mission.

Movement of plasma to higher latitudes by EIA is known to relate to eastward electric field/EEJ and thermospheric meridional neutral wind. Experiments from GPS measurements that unveil thermospheric meridional neutral wind effect on plasma transportation in the F region are very few compared with electric field/EEJ. This work includes examples of thermospheric meridional neutral wind effects on GPS TEC measurements and their roles in transportation of plasma compared to electric field/EEJ.

We propose a simple explanation of the prolonged existence of pancake-like electron velocity distributions in the radiation belts. The pancake-like distribution function is characterized by a longitudinal particle velocity (along the magnetic field) of the order of the thermal velocity of the background plasma. The parameters of the tablet-like distribution function are refined. The stability of these distributions is examined.

We study geomagnetic field variations from 1 min data at three Antarctic sites (Mario Zucchelli Station, Scott Base, Talos Dome) along the 80° S geomagnetic parallel. The daily variation depends on local time, due to the polar extension of midlatitude ionospheric currents. The ~1–7 mHz power maximizes around 12 MLT, close to the cusp, and the coherence does so between stations around 24 MLT. The wave propagation is consistent with a daytime solar wind source and with nighttime substorm processes.

The Earth's magnetic field creates a magnetic bulk all around it called the magnetosphere. This bulk a priori protects us from the particles coming from the sun but sometimes undergoes violent events such as interplanetary coronal mass ejections. These cause the entry of particles into the magnetosphere, which can be harmful for satellites. In this paper, we performed a statistical study to characterize the interplanetary coronal mass ejections and their ability to disturb the magnetosphere.

we present the first multi-year results of the climatology of horizontal winds obtained during a period of 26 months. We compare the observed climatologies of neutral winds to that provided by the recently updated Horizontal Wind Model (HWM14) in order to validate that model's predictions of the thermospheric wind patterns over the eastern portion of Africa. HWM14 generally compares well with the horizontal winds, but significant magnitude and phase differences remain in certain seasons.