Measurements of the electric field and neutral wind in the ionosphere are important for understanding energy flows or electric currents. With incoherent scatter radars (ISRs), we can measure the velocity of the ions, which depends on both the electrical field and the neutral wind. In this paper, we investigate methods to use ISR data to find reasonable values for both parameters. We find that electric field can be well measured down to 125 km height and neutral wind below this height.

This paper presents an analysis of high-resolution optical and radar observations of a phenomenon called fragmented aurora-like emissions (FAEs) observed close to aurora in the high Arctic. The observations suggest that FAEs are not caused by high-energy electrons or protons entering the atmosphere along Earth's magnetic field and are, therefore, not aurora. The speeds of the FAEs and their internal dynamics were measured and used to evaluate theories for how the FAEs are produced.

We use a computer code to study how a particular plasma effect, the Hall effect, changes how plasma behaves and interacts with magnetic fields behind planets in the magnetotail. We find that when the scale of the Hall effect is big enough compared to the scale of the magnetotail, plasma behavior is no longer symmetric. Measurements of magnetic activity and structure vary in time and differ between opposite sides of the tail. This fits well with findings from spacecraft data and other models.

In the present work, the lunar semidiurnal tide (M₂) was investigated in the equatorial plasma bubble (EPB) zonal drifts over Brazil from 2000 to 2007. On average, the M₂ contributes 5.6 % to the variability of the EPB zonal drifts. A strong seasonal and solar cycle dependency was also observed, the amplitudes of the M₂ being stronger during the summer and high solar activity periods.

We present a detailed account of the science programme PRESTO (PREdictability of the variable Solar–Terrestrial cOupling), covering the period 2020 to 2024. PRESTO was defined by a dedicated committee established by SCOSTEP (Scientific Committee on Solar-Terrestrial Physics). We review the current state of the art and discuss future studies required for the most effective development of solar–terrestrial physics.

The Sun's magnetic field is carried across space by the solar wind – a hot plasma stream of ions and electrons – forming the interplanetary magnetic field (IMF). The IMF can introduce asymmetries in the Earth's magnetic field, giving plasma flowing within it a direction dependent on IMF orientation. Electric currents in near-Earth space can also influence these plasma flows. We investigate these two competing mechanisms and find that the currents can prevent the IMF from controlling the flow.

Our model calculations indicate that meteoric smoke particles (MSPs) influence both the magnitude and shape of the electron temperature during artificial heating. Others have found that current theoretical models most likely overestimate heating in the D-region compared to observations. In a future study, we will compare our results to observations of the electron temperature during heating to investigate if the presence of MSPs can explain the discrepancy between model and observations.