Venus has no intrinsic magnetic field. On the other hand, we discover that an interplanetary magnetic field may nevertheless penetrate the planetary ionosphere by the diffusion process and reach the planetary surface when the solar wind condition remains for a sufficiently long time, between 12 and 54 h, depending on the condition of ionosphere.

The frontal region of Earth's magnetic shield, the magnetopause, is very often impacted by high-speed jets of solar origin that can trigger multiple geophysical effects. Our study brings novel results that contribute to understanding the dynamics of such structures. We performed advanced simulations and demonstrate the formation of a peculiar particle distribution of the energy (the crescent-shaped electron distribution) at the edges of plasma jets interacting with the magnetopause.

Atmospheric ozone plays a vital role, absorbing the ultraviolet solar radiation and heating the air, thus forming the stratosphere itself. If not absorbed, UV radiation would reach Earth's surface in amounts that are harmful to a variety of lifeforms. Climate change may lead to increasing ozone depletion, especially in the Arctic. Observation and prediction of the ozone variability are crucial for the investigation of its nature and the prediction of potential increase in surface UV radiation.

This paper presents a completely new method based on a new data analysis technique (ALIF) to determine both the environmental and instrumental backgrounds applied to all the DEMETER satellite electric and magnetic field data over L'Aquila's seismic region. Interestingly, on 4 April 2009, when DEMETER flew exactly over L'Aquila at 20:29 UT, an anomalous signal was observed at 333 Hz on both the electric and magnetic field data, whose characteristics seem to be related to pre-seismic activity.

Based on our simulation results, both temperature change and meridional neutral wind could cause the 630.0 nm nightglow intensity to vary, while the latter is more effective. An unexpected aspect of the results is the non-monotonic dependence of the emission rate on temperature, featuring a turning point as the temperature changes. Our findings of these turning temperature tendencies can guide future modeling attempts to match the observed nightglow brightness intensities.

This paper investigates the combined relationship between the GPS TEC and DPS TEC, and validations of IRI TEC and NeQ TEC models. Our findings reveal the suitability of DPS TEC, IRI TEC, and NeQ TEC in place of GPS TEC. The DPS TEC predicts GPS TEC very well during the daytime when PEC contribution is often negligible; however, the dusk period requires a substantial correction. Thus, the changed TEC obtained could be used to improve models for the equatorial station in Africa.

Pressure and anisotropy profiles from trapped ions in the ring current as observed from energetic neutral atom images are compared to numerical simulations for the first time. The results show evidence for short time and spatially localized injections from the plasma sheet.

Downward stratospheric intrusions are well known as an important source of tropospheric ozone. In the light of the present understanding, several unanswered questions remain regarding the use of VHF radars to identify stratospheric intrusions. Our study found that the radar-observed strong downdrafts preceding the rapid tropopause ascent are a strong diagnostic for possible intrusions. This will have important implications for air-quality monitoring and long-term estimation of troposphere ozone.

A new plasma intrusion or preonset aurora scenario of substorm triggering proposed by Nishimura et al. (2010) needs to be tested. To test the scenario, we revisited three of their substorm events in detail, based on THEMIS ground-based all-sky imager data. We list a series of open questions for testing the scenario further in future studies.

The extraction of the magnetic signal induced by the oceanic M2 tide is typically based solely on the temporal periodicity of the signal. Here, we propose a system of tailored trial functions that additionally takes the spatial constraint into account that the sources of the signal are localized within the oceans. This construction requires knowledge of the underlying conductivity model but not of the inducing tidal current velocity.

Hall current variations in different time sectors during six magnetic storms of the summer seasons in 2003 and 2005 are examined. The sequence of the phenomena, their structure, positions and the strength of the polar and the auroral Hall electrojets were investigated using scalar magnetic field measurements obtained from the CHAMP satellite. We analyzed the correlations and the regression relations of the electrojets with auroral and ring current activity, the IMF, and solar wind parameters.

We present the first observations of perturbations in radio communications, the ionosphere, cosmic rays, and the geomagnetic field over Mexico due to space weather events.

The features of ULF waves are statistically studied on the magnetotail stretched magnetic field lines (8 RE < R < 32 RE) by using 8 years of THEMIS data. The occurrence rates of ULF waves are higher in the post-midnight region than pre-midnight region. The frequency decreases with increasing radial distance of 8–16 RE and could be explained by much more standing waves in this region than in the region of 16–32 RE. The wave frequency is higher after the substorm onset than before it.

We employ multipoint observations of the Van Allen Probes, THEMIS, GOES and Cluster to present case and statistical studies of the electromagnetic field, plasma and particle response to interplanetary (IP) shocks observed by Wind. We perform a statistical study of E_y variations of the electric field and associated plasma drift flow velocities for 60 magnetospheric events during the passage of interplanetary shocks.

We analysed the turbulent processes in the Earth's magnetotail in the regions of magnetic field dipolarization and compared them with known models. We used spectral and statistical methods for analysis measurements from the Cluster-II mission. We have obtained a significant difference for turbulent processes depending on observed scales. Our results can be interesting for classification of the turbulent processes in both hydrodynamics and magnetohydrodynamics environments.

This paper describes "beam tracking", a new technology for measuring velocity distributions in the solar wind with a plasma spectrometer, that allows the order of magnitude speedup in data acquisition needed for studying ion-scale turbulence. The basic idea is that the spectrometer should only sample the energy–elevation–azimuth range where the solar wind is expected to reside. The paper shows how the technique can be implemented and illustrates its performance and robustness through simulation.

The variability of the Earth's ionosphere (the electrified region of the Earth's upper atmosphere) results from external forcing from above (through solar activity and space weather effects) and from below (via natural sources such as lightning storms and tectonics). Bombing raids over Europe during World War II were used to determine the quantitative impact of explosions on the ionosphere. It was found that raids using more than 300 tonnes of explosives weakened the ionosphere for up to 5 h.

This study shows the width of the meteor height distribution (FWHM) is well correlated with the atmospheric pressure, not only experimentally but theoretically. From the correlation analysis, we found that the FWHM provides the best estimation of the temperature at the height layer below the meteor peak height by 2–3 km. We also proved a meteor echo height ceiling effect (MHC) is primarily controlled by the atmospheric conditions, and this enables the FWHM to estimate the temperature accurately.

In this contribution, we analyse the performance of the Swarm onboard GPS receiver and present the approach for determination of the IfE Swarm kinematic orbit with PPP. The differences between our kinematic orbits and ESA reduced-dynamic orbits are at 1.5 cm, 1.5 cm and 2.5 cm level in along-track, cross-track and radial directions, respectively. A comparison with SLR underlines an accuracy of the kinematic orbits of 3–4 cm.

Data analysis of the geomagnetic field is needed for space weather prediction. Conventional techniques do not always provide sufficient efficiency. We suggest new techniques for processing and analyzing geomagnetic data based on the wavelet transform for studying the dynamics and spatiotemporal distribution of geomagnetic perturbations. The paper discusses prestorm short-term increases of geomagnetic activity and the features of different magnetospheric processes for increased solar activity.

A VLF chorus is a very intense electromagnetic plasma wave that is naturally excited as a succession of discrete emissions near the magnetic equatorial plane outside the plasmasphere. We introduce a mechanism of chorus excitation under conditions when known mechanisms become ineffective. This kind of excitation is related to the amplification of short electromagnetic pulses from the noise level even in a stable plasma. Obtained results can explain some important features of the chorus emissions.