By using magnetic field recordings sampled at 50 Hz by Swarm A and C satellites around the quasi-coplanar orbit configuration, near 1 October 2021, we investigate the properties of kilometer-scale field-aligned currents (FACs) at auroral latitudes. The kilometer-scale (0.2-5 km) FACs exhibit short-lived (<1 s) randomly appearing large current density spikes (partly exceeding 100 µA m-2). Preferred occurrences are the noon to prenoon (nightside to dusk) sector around 80° (70°) MLat, respectively.

The lack of ground observation instruments and the vast ocean coverage make the Southwest Indian Ocean (SWIO) region difficult to access and poorly studied. For gathering ground-based camera information, satellite measurements have been used with the primary goal of characterizing both sites Saint-Denis of Reunion Island and Antananarivo Madagascar in terms of cloudiness. This study shows the particularity of each site and enhances our understanding of cloud properties, particularly in the SWIO.

The magnetic mirror force bends the orbits of electrons precipitating into the atmosphere. It has been suggested that relativistic electrons make much less ionization due to the force than if it did not exist, but the actual effectivity in the atmospheric electron density has not been revealed. We used conjugated observational data from the ELFIN (Electron Losses and Fields INvestigation) satellite and the EISCAT (European Incoherent SCATter scientific radar system) Tromsø radar to find that the electron density decreased by about 40 % at 80 km altitude because of the force.

This study addresses the design of next-generation incoherent scatter radar experiments used to study the ionosphere, particularly with systems that have multiple sites. We have developed a method to estimate uncertainties of measurements of plasma density, temperature, and ion drift. Our method is open-source, and helps to optimize radar configurations and assess the effectiveness of an experiment. This method ultimately serves to enhance our understanding of Earth's space environment.

Analysis of 10 years of continuous measurements provided MMARIA/SIMONe Norway and MMARIA/SIMONe Germany reveals that the divergent and vortical motions in the mesosphere and lower thermosphere exchange the dominant role depending on the height and the time of the year. At summer mesopause altitudes over middle latitudes, the horizontal divergence and the relative vorticity contribute approximately the same, indicating an energetic balance between mesoscale divergent and vortical motions.

This research explores how hydrogen ions and oxygen ions move and gain energy in Earth’s magnetosphere at high altitudes and latitudes. Using Monte Carlo simulations, predictions of mean particle theory, and corresponding observations, we compared different energy profiles of hydrogen and oxygen ions across polar-wind, aurora, cusp, and central-polar-cap regions. Our findings reveal that unique interactions in each area affect energy gain differently, with implications for future space weather models.

Our study probes how solar-wind disturbances affect cosmic rays on Earth during solar eruptions. Increased cosmic rays during heightened solar wind suggest that turbulence scatters and redistributes them, prolonging intensity. Understanding these effects is crucial for accurate cosmic-ray data interpretation.

In this work, the investigation of Rossby-Khantadze waves with sheared zonal flows in E-ionosphere is presented. The spatially inhomogeneous Earth's angular velocity and background magnetic field are considered. The field inhomogeneity makes the coupling of Rossby and Khantadze waves. The numerical work of obtained linear frequencies is done. By using the method of multiple scale, we obtained a new Boussinesq nonlinear equation. Also, we obtain the travelling solitary structures.

We use NO column density data from the Syowa station in Antarctica from 2012–2017. We compare these ground-based radiometer observations with results from a global atmosphere model to understand the year-to-year and day-to-day variability, shortcomings of current electron forcing, and how geomagnetic storms are driving the variability of NO. Our results demonstrate an underestimation in the magnitude of day-to-day variability in simulations, which calls for improved electron forcing in models.

This study explores the influence of temperature anisotropy and kappa-distributed suprathermal particles on electromagnetic ion cyclotron (EMIC) wave propagation in a multi-ion magnetospheric plasma. Results show that higher anisotropy enhances wave growth, while an increasing kappa value suppresses it, leading to thermalization. These findings have key implications for radiation belt electron loss and space weather modeling. Future work should incorporate nonlinear effects and observational validation.

Traveling ionospheric disturbances are plasma density fluctuations usually driven by atmospheric gravity waves in the neutral atmosphere. The aim of this study is to attribute multi-instrument observations of traveling ionospheric disturbances to gravity waves generated in the upper atmosphere at high latitudes or gravity waves generated by tropospheric weather systems at midlatitudes.

Interplanetary shock waves are one of the major forms of heliospheric transients that can have a profound impact on solar wind plasma and magnetic field conditions and accelerate charged particles to high energies. This work performs an extensive statistical analysis to detail how some of the key solar wind turbulence parameters, critical for understanding particle acceleration, are modified by the interplanetary shocks waves.