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At times when auroras erupt on the sky, the magnetic field surrounding the Earth undergoes rapid changes. On the ground, these changes can induce harmful electric currents in technological conductor networks, such as powerlines. We have used magnetic field observations from North Europe during 28 such events and found consistent behavior that can help to understand, and thus predict, the processes that drive auroras and geomagnetically induced currents.

We investigated the relationship between PMSE layers and the solar cycle. Our results indicate that PMSE altitude, echo power, and layer thickness are on average higher during solar maximum than solar minimum. Higher electron densities at ionospheric altitudes might be necessary to observe multi-layered PMSE. We observed that the thickness decreases as the number of multi-layers increase. We hypothesized that the thickness of PMSE layers may be related to the vertical wavelength of gravity waves

The plasma environment of comet 67P provides a unique laboratory to study plasma phenomena in the solar system. Previous studies have reported the existence of mirror modes at 67P but no further systematic investigation has so far been done. This study aims to learn more about these waves. We investigate the magnetic field measured by Rosetta and find 565 mirror mode signatures. The detected mirror modes are likely generated upstream of the observation and have been modified by the plasma.

The 1-D column model has been used extensively in studying the Martian atmosphere at various landing sites. In this study, we investigated the sensitivity of the column model to its initial parameters. The results of the model were compared with Curiosity rover measurements. Initial value of airborne dust and surface temperature had the greatest influence on the temperature prediction, while the initial value of atmospheric moisture modified the humidity prediction the most.

Solar tides in the atmosphere are driven by solar heating on the dayside of the Earth. They result in large-scale periodic motion of the upper atmosphere. This motion can be measured by ground-based radars. This paper shows that making measurements at a higher time resolution than the standard operation provides a better description of higher frequency tidal variations. This will improve the inputs to empirical atmospheric models and the benefits of data assimilation.

Magnetosheath jets are structures of enhanced plasma density and/or velocity in a region of near-Earth space known as the magnetosheath. When they propagate toward the Earth, these jets can disturb the Earth's magnetic field and cause hazards for satellites. In this study, we use a simulation called Vlasiator to model near-Earth space and investigate jets using case studies and statistical analysis. We find that jets that propagate toward the Earth are different from jets that do not.

The solar wind interacts with the planets in the solar system, and creates a supersonic shock in front of them. The upstream region of this shock contains many complicated phenomena. One such phenomenon is small-scale structures of strong magnetic fields (SLAMS). These SLAMS have been observed at Earth, and are important in determining the properties of space around the planet. Until now SLAMS have not been observed at Mercury, but we here show for the first time that SLAMS exist also here.

According to the plasma drift theory, charged particles will drift when they are subjected to external forces, thus generating a drift current. In this paper, we give the formula of drift current in F and analyze the properties of drift current such as magnitude and distribution, and explains the effect of the heating wave and magnetic field angle on the drift current. This work establishes the basis for the excitation and propagation of ELF waves in the ionosphere.

Gravity waves (GWs) are waves in Earth's atmosphere and can for example cause cloud ripples. Under certain conditions, these waves can propagate up into the ionosphere. Here, they can cause ripples in the ionosphere plasma, observable as oscillations of the plasma density. Therefore, GWs contribute to ionospheric variability, making them relevant for space weather prediction. Additionally, the behavior of these waves allows us to draw conclusions about the atmosphere at these altitudes.

We dealt with the most intense magnetic storm of the 20th century, which took place on 13–15 May 1921. It was also observed at Stará Ďala (present-day Hurbanovo). However, the record was not complete. We estimated the missing sensitivity scale values and presented the resulting digitized Stará Ďala’s data for 13–15 May 1921. The data were compared with the records from other observatories. The analysis suggests that the auroral oval got close to Stará Ďala in the morning hours on 15 May 1921.