In this study, we present the comparison between an auroral model and EISCAT radar electron densities during pulsating aurorae. We test whether an overpassing satellite measurement of the average energy spectrum is a reasonable estimate for pulsating aurora electron precipitation. When patchy pulsating aurora is dominant in the morning sector, the overpass-averaged spectrum is found to be a reasonable estimate – but not when there is a mix of pulsating aurora types in the post-midnight sector.

The relationships between auroral activity and the solar-wind conditions are modeled with a machine-learning technique. The impact of various solar-wind parameters on the auroral activity is then evaluated by putting artificial inputs into the trained machine-learning model. One of the notable findings is that the solar-wind density effect on the auroral activity is emphasized under high solar-wind speed and weak solar-wind magnetic field.

To study long-term trends in the mesosphere and lower thermosphere (70–100 km), we established two summer length definitions and analyzed the variability over the years (2004–2020). After the analysis, we found significant trends in the summer beginning of one definition. Furthermore, we were able to extend one of the time series up to 31 years and obtained evidence of non-uniform trends and periodicities similar to those known for the quasi-biennial oscillation and El Niño–Southern Oscillation.

It has long been known that particles get accelerated close to the speed of light in the near-Earth space environment. Research in the last decades has also clarified what processes and waves are responsible for the acceleration of particles. However, it is difficult to quantify the scale of the impact of various processes competing with one another. In this study we present a methodology to quantify the impact waves can have on energetic particles.

Detection of Ionosphere Anomalies (DIA) for detection, identification, and analysis of ionosphere anomalies from satellite spectrograms and time series row data from instruments onboard the DEMETER satellite was designed. Using this software, the analyses of ionosphere parameter variations caused by various factors are provided. The scientific data processing and visualization technologies used in the development of DIA can be used in the creation of software for other scientific space missions.

The study presents long-term altitudinal changes and variability (spatial and temporal; during 2000–2017) in the coverage of snow and glaciers in one of the world’s largest mountainous regions, i.e., the Hindu Kush Himalayan (HKH) region. The western zone and high-altitude regions (above 6000 m) show no significant decline in snow cover, whereas the lower-altitude regions (< 6000 m) show a variable but statistically significant decline in snow cover in the central and eastern zones (5 %–15 %).

We propose a new method that combines observations and models to estimate the loss of atmosphere by ion escape from unmagnetized planets. The proposed method allows us to estimate the ionospheric ion escape rate from one bow shock crossing using ion and magnetic field observations. This new technique is applicable to studies on how escape depends on different parameters, work on escape rates during extreme solar wind conditions, and research on escape in the early solar system and at exoplanets.

Revealing the nature of Mercury’s internal magnetic field is one of the primary goals of the BepiColombo mission. Besides the parametrization of the magnetic field contributions, the application of a robust inversion method is of major importance. The present work provides an overview of the most commonly used inversion methods and shows that Capon’s method as well as the Tikhonov regularization enable a high-precision determination of Mercury’s internal magnetic field up to the fifth degree.

During auroral substorms, the ionospheric electric currents change rapidly, and a large amount of energy is dissipated. We combine ionospheric current data derived from the Swarm satellite mission with the substorm database from the SuperMAG ground magnetometer network. We obtain statistics of the strength and location of the currents relative to the substorm onset. Our results show that low-earth orbit satellites give a coherent picture of the main features in the substorm current system.

Magnetospheric physics is in an extremely vibrant phase, with a number of ongoing and highly successful missions, e.g., Cluster, THEMIS, Van Allen Probes, and the MMS spacecraft, providing the most amazing observations and data sets. Since there are many fundamental and unsolved problems, in this paper I have addressed selected topics of ULF wave–charged particle interactions which encompass many special fields of radiation belt, ring current and plasmaspheric physics.

This paper presents a study of millihertz magnetic pulsations seen in the magnetosphere and on the Earth under quiet space weather conditions. We found that these fluctuations appear in the magnetosphere as soon as disturbances with the same frequency vanish in the solar wind. The results of this work show the possibility of a substorm developing under absolutely quiet external conditions and allow us to assume that these pulsations represent a substorm preparatory phase.