Magnetometers are essential for monitoring the Earth’s magnetic field in applications such as geophysics, space weather, navigation, and volcanic studies. While professional-grade instruments provide high reliability, their cost limits spatial coverage, particularly in remote regions. This study presents a comparative analysis of five ground-based magnetometers deployed simultaneously at Universidad Adventista de Chile (36.64° S, 71.99° W) from 5–8 August 2025. Noise, signal stability, and response to geomagnetic variations were evaluated, emphasizing the influence of ambient temperature. Fluxgate and subsurface-deployed instruments showed higher consistency and reduced thermal sensitivity, while low-cost magneto-inductive sensors exhibited strong linear temperature dependence, sometimes with temporal delays. Inter-instrument correlation analyses highlighted performance differences and the trade-offs between cost and reliability. The results demonstrate that low-cost magnetometers, if carefully deployed and calibrated, can complement professional-grade sensors, improve spatial coverage, and provide valuable geomagnetic observations in regions with limited infrastructure and logistical constraints.

In this work, we used a dataset of 60 relativistic electron enhancement events measured at geostationary orbit (GEO) to study the correlation between the >2 MeV and >4 MeV electron fluxes. We then use the fluxes at GEO to compare against in-situ measurements from the Van Allen Probes mission and study the radial response of outer belt fluxes and the correlation between the fluxes at GEO and those closer to the Earth. The enhancement events occurred between 1 October 2012 and 31 December 2017 and were identified using Geostationary Operational Environmental Satellite (GOES) 15 >2 MeV fluxes at GEO. We compare with fluxes measured by the Van Allen probes Energetic Particle, Composition and Thermal Plasma Suite Relativistic Electron-Proton Telescope (ECT-REPT) between 2.5 < L < 6.0 at E = 2.1 MeV and E = 4.2 MeV. We found that the response of the radiation belts during enhancement events is very homogeneous for L > 4.0 and extremely similar for L > 5.0. Post-enhancement maximum fluxes show a remarkable correlation for all L > 4.0 at both the 2.1 MeV and 4.2 MeV energies, indicating that modeling or forecasting efforts of the outer radiation belt using data from geostationary orbit are justified.

Geomagnetic storms cause significant disturbances in the high-latitude ionosphere. Studying these impacts is challenging due to the complex magnetosphere-ionosphere coupling and physical mechanisms involved. Here, we utilized measurements from the Global Navigation Satellite System (GNSS) network to calculate the Total Electron Content (TEC) across GNSS receivers at magnetically conjugate points in Antarctica, Canada, and the United States. We analyzed 25 geomagnetic storms during Solar Cycle 24 (SC24), examining the interhemispheric behavior and differences in TEC under varying seasonal and solar conditions, driven by distinct geomagnetic storm drivers. Our results revealed differences in the interhemispheric velocity of TEC disturbances moving from the poles toward the equator. While comparisons of disturbance velocities with various solar wind and magnetospheric parameters did not show clear relationships, a notable correlation emerges when the rate of decrease in the Dst index is larger than -60 nT/h during storms. This correlation is more pronounced in the Northern Hemisphere than in the Southern Hemisphere. Furthermore, we identified significant variations in the timing of the maximum Vertical TEC (VTEC) occurrence relative to the onset of the storm's main phase. Finally, we studied the relationship between the velocities and seasonal variations, including the different storm drivers, and the results do suggest true hemispherical differences.

A comparative overview of Terrestrial and Martian space weather is presented, with emphasis on applying the tools of complexity and nonlinear dynamics to study the spatiotemporal dynamics and structures of sun-Earth and sun-Mars space environment. The following topics are reviewed: (1) complex systems approach to solar atmosphere and solar wind; (2) complex systems approach to planetary bow shock and magnetosphere-ionosphere; (3) Martian space weather, bow shock, and magnetosphere-ionosphere; (4) imaging planetary magnetosphere-ionosphere.

In the present study, the influence of the solar wind dynamic pressure on the plasma and magnetic pressures of the magnetosphere is studied. We use 11-year Time History of Events and Macroscale Interactions during Substorms (THEMIS) instruments for plasma and magnetic field measurements in the magnetosphere and the OMNI database for solar wind dynamic pressure and IMF data. We focus on the effects of the solar wind dynamic pressure (PSW) and consider only times in which the interplanetary magnetic field (IMF) components are within +/- 5 nT. We find that the plasma pressure inside the magnetosphere follows the solar wind dynamic pressure and that an increase in PSW also influence the day-night pressure asymmetry. Our analysis also reveals the existence of ion and electron drifts from midnight toward the dusk and dawn sectors, respectively. We observe a local magnetic pressure minimum located near a plasma pressure maximum at around 11 RE on the nightside. Comparing the effect of PSW on both plasma and magnetic pressures, we observe trends which are consistent with the diamagnetic properties of plasmas. In general, the distribution of plasma pressure within the Earth's magnetosphere is an important criterion for evaluating the magnetostatic equilibrium and electric current system. The outcome of this study should provide additional methodologies for the characterization of key plasma characteristics within the magnetosphere. Magnetospheric activity and space weather are driven by the interaction of the solar wind and the Earth's magnetic field. The solar wind dynamic pressure and interplanetary magnetic field (IMF) are two important factors that affect the behavior of the Earth's magnetosphere. The interaction between these two factors are complex and can have significant effects on our planet. Based on 11-year plasma and magnetic field measurements, obtained from THEMIS satellites, we investigated the effect of solar wind dynamic pressure on the plasma and magnetic pressures within the Earth magnetosphere. In this study, we show that changes in the plasma pressure within the magnetosphere are linked to variations in the solar wind dynamic pressure. Our findings confirm that the plasma pressure inside the magnetosphere is mainly controlled by the solar wind dynamic pressure, which can be attributed to pressure balance. Overall, the distribution of plasma pressure within the Earth's magnetosphere is a key parameter for evaluating the magnetostatic equilibrium and electric current system. Our results are expected to offer scientists additional methodologies for characterizing main plasma parameters in the magnetosphere. Increase in solar wind dynamic pressure leads to increase in plasma and magnetic pressures in the magnetosphere Larger solar wind dynamic pressure make the plasma pressure more symmetric around the Earth Observations reveal a local magnetic pressure minimum located near a plasma pressure maximum around 11RE on the nightside

The start of the space era marked the discovery of the Earth’s radiation belts. Sixty-five years after that discovery, there are still many unknowns in its dynamics, but there is also a lot of understanding about many processes. This review summarizes a broad overview of a particular topic: the effect of geomagnetic storms on the radiation belts from a historical perspective. In writing this review, we aim to preserve, rescue, and put together the initial attempts at understanding the radiation belts since most of the literature is somewhat hidden or forgotten. This is particularly relevant for students and young researchers, who did not live the initial stages of the space age. To help in this endeavor, we included the description of the main satellite missions and their instruments starting from the first satellites like Sputnik and Explorer and finishing with contemporary missions like Van Allen Probes and Arase, and different techniques. In this review, we also tried to include the majority of points of view about the dynamics of radiation belts, giving everybody a chance to analyze them and make their conclusions. We selected a limited number of papers from one side that are representative with respect to a specific topic and from the other side help to see the evolution of our knowledge about radiation belts. We made a special tribute to pioneering works of the 50s and 60s and also included some interesting results, which are almost impossible to read in English. So this review is a good starting point for navigating the ocean of modern space physics related to the outer radiation belt.

The Earth's magnetosphere is filled with a collisionless plasma that exhibits non-Maxwellian particle distributions which are well described by Kappa functions. In contrast to the Maxwellian, the Kappa contains not only density and temperature but also the kappa index that allows us to characterize the energetic tails. In this study, we analyze the response of the ion and electron Kappa distributions, obtained by fitting ion and electron fluxes measured by the five THEMIS satellites, to changes of the solar wind dynamic pressure. It was found that the solar wind dynamic pressure strongly affects the values of the kappa index, and that its impact depends on the magnetic local time (MLT). In particular, there is a significant dawn-dusk asymmetry for low PSW values which is enhanced in the night side. Further, we observe a narrow partial ring-shaped structure at different azimuthal extension that divides the plasma into two clearly defined domains. The results obtained reflect the global reconfiguration of the magnetosphere caused by variations of the solar wind dynamic pressure. Kappa distribution parameters and their average values for different ranges of PSW and MLT are provided, which we believe will contribute as realistic inputs to the modeling of the magnetosphere. The Kappa distribution function, which combines the Maxwellian-type and the power-law distributions, has been widely used in literature to describe particle populations in space and astrophysical plasmas. In such environments, ions and electrons rarely experience collisions and they are out of thermal equilibrium, which allows us to get insights into the mechanism of energy transfer in these plasmas. The goal is to investigate the roles of non-thermal particle distributions, and their response to solar wind dynamic pressure in poorly collisional plasma environments such as the Earth magnetosphere. The availability of high cadence Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite data have enabled us to conduct this statistical analysis using THEMIS and OMNI database. Our findings confirm that the ion and electron kappa parameters exhibit distinct behaviors when subjected to the dynamic pressure exerted by the solar wind. Moreover, we find an interesting narrow partial ring shaped structure at different azimuthal extension exhibiting a local minimum for ion kappa parameters, and a local maximum for electron kappa parameters. The behavior of Kappa distribution parameters in the Earth magnetosphere in response to the variation of the solar wind dynamic pressure is studied The solar wind dynamic pressure strongly influence ion and electron kappa indices The core energy (Ec) exhibits a significant dawn-dusk asymmetry for ions and much weaker for electrons in various range of PSW

In this work, we discuss the problems associated with the formation of the outer radiation belt (ORB) taking into account previous results, including the recent ones. In our opinion, the traditional approaches to the dynamics of the ORB have the following problems: • inconsistency between the times provided by the popular “quasilinear” approach to the ORB description and the observed electron acceleration times; • impossibility to describe ORB dynamics during magnetospheric storms using the “quasilinear” approach when the particle fluxes after storm restore to their pre-storm values, i.e., belong to the storms of the third type according to Reeves et al. (2003, https://doi.org/10.1029/2002GL016513 ) classification; • impossibility of explaining the Tverskaya’s relation, which connects the position of the maximum of the relativistic flux formed after storm with the minimum value of the Dst/SYM-H variation, as well as the acceleration of relativistic electrons during magnetospheric substorms even in the absence of storms. We show that such difficulties do not appear if we take into account the large- scale magnetospheric dynamics, including auroral oval shift toward low latitudes during storms, substorm injections into the region of depressed magnetic field during storm recovery phase and the action of the adiabatic mechanism of electron deceleration and acceleration. The action of stochastic mechanisms of ORB acceleration is also discussed.

Abstract Since the discovery of the large‐scale field‐aligned currents it is widely acknowledged that gaps exist between the Region 1 (R1) and Region 2 (R2) currents in which the current values are relatively small as compared to neighboring regions. Assuming that the field‐aligned currents are generated by plasma pressure gradients, we analyzed data collected by the THEMIS satellites between 2007 and 2011 to identify regions with very low plasma pressure gradients (pressure plateaus), which could be responsible for the appearance of these gaps. It was found that the pressure profiles with low radial gradients are typically located between 8 and 10 Radii around the Earth. Projections of pressure plateau regions onto ionospheric altitudes, for both individual events and on a statistical basis, coincide with the locations of gaps between Iijima and Potemra field‐aligned currents. The role played by identified pressure plateaus in shaping the pattern of large‐scale field‐aligned currents is discussed.

We analyzed the applicability of a hydrodynamic approach to the analysis of large-scale magnetospheric dynamics in the conditions of quiet geomagnetic activity. The main parameter, determining the applicability of the ideal MHD, is the ratio between the Alfvén and plasma velocities. We obtained the 2D distribution of this parameter using data of the THEMIS mission at geocentric distances <20 RE, and showed that not only the ring current region can be described suggesting full pressure balance. The external part of the ring current, which is localized in the surrounding the Earth plasma ring and earlier considered as a plasma sheet continuation, can be regarded as a stress balance region as well. Azimuthal plasma pressure gradients in this region create a system of large-scale field-aligned currents. Their closing in the ionosphere generates a large-scale convection in the ionosphere and magnetosphere. The mechanism of the large-scale convection control due to "penetration" of large-scale solar wind magnetic field is discussed. We discuss the role of turbulent transport in the analysis of magnetospheric regions, in which high level of turbulence is observed simultaneously with large-scale stress balance.

The most recent findings on the dynamics of the outer radiation belt (ORB) and the physics of magnetospheric substorms are examined. Specifically, we investigate the relationship between storm time substorms and the energetic electron population that forms the ORB. Traditionally, storm time substorms have been considered as the primary source of energetic electrons, which are further accelerated during storms to contribute to the formation of the ORB. However, several observations have demonstrated that large magnetospheric substorms can generate high-energy electrons even in the absence of magnetic storms. Substorms introduce dispersionless injections of energetic electrons deep into the magnetosphere from the geosynchronous orbit during storm times. The injected electrons undergo additional acceleration via the betatron mechanism during the storm recovery phase, thus increasing the ORB population. To gain a better understanding of this process, it is crucial to study plasma sheet turbulence, substorm onset processes, and the brightening of auroral arcs. By analyzing the aforementioned findings, this study aims to highlight the need for reanalyzing of the role of auroral processes in the formation of the ORB.

In this work, we evaluate the SUPIM-INPE model prediction of the 14 December 2020, total solar eclipse over the South American continent. We compare the predictions with data from multiple instruments for monitoring the ionosphere and with different obscuration percentages (i.e., Jicamarca, 12.0°S, 76.8°W, 17%; Tucumán 26.9°S, 65.4° W, 49%; Chillán 36.6°S, 72.0°W; and Bahía Blanca, 38.7°S, 62.3°W, reach 95% obscuration) due to the eclipse. The analysis is done under total eclipse conditions and non-total eclipse conditions. Results obtained suggest that the model was able to reproduce with high accuracy both the daily variation and the eclipse impacts of E and F1 layers in the majority of the stations evaluated (except in Jicamarca station). The comparison at the F2 layer indicates small differences (<7.8%) between the predictions and observations at all stations during the eclipse periods. Additionally, statistical metrics reinforce the conclusion of a good performance of the model. Predicted and calibrated Total Electron Content (TEC, using 3 different techniques) are also compared. Results show that, although none of the selected TEC calibration methods have a good agreement with the SUPIM-INPE prediction, they exhibit similar trends in most of the cases. We also analyze data from the Jicamarca Incoherent Scatter Radar (ISR), and Swarm-A and GOLD missions. The electron temperature changes observed in ISR and Swarm-A are underestimated by the prediction. Also, important changes in the O/N2 ratio due to the eclipse, have been observed with GOLD mission data. Thus, future versions of the SUPIM-INPE model for eclipse conditions should consider effects on thermospheric winds and changes in composition, specifically in the O/N2 ratio.

EDITORIAL article Front. Astron. Space Sci., 17 February 2022 | https://doi.org/10.3389/fspas.2021.763190

Among the fundamental and most challenging problems of laboratory, space, and astrophysical plasma physics is to understand the relaxation processes of nearly collisionless plasmas toward quasi-stationary states; and the resultant states of electromagnetic plasma turbulence. Recently, it has been argued that solar wind plasma β and temperature anisotropy observations may be regulated by kinetic instabilities such as the ion-cyclotron, mirror, electron-cyclotron, and firehose instabilities; and that magnetic fluctuation observations are consistent with the predictions of the Fluctuation-Dissipation theorem, even far below the kinetic instability thresholds. Here, using in-situ magnetic field and plasma measurements by the THEMIS satellite mission, we show that such regulation seems to occur also in the Earth's magnetotail plasma sheet at the ion and electron scales. Regardless of the clear differences between the solar wind and the magnetotail environments, our results indicate that spontaneous fluctuations and their collisionless regulation are fundamental features of space and astrophysical plasmas, thereby suggesting the processes is universal.

Black carbon (BC) from fossil fuel and biomass combustion darkens the snow and makes it melt sooner. The BC footprint of research activities and tourism in Antarctica has likely increased as human presence in the continent has surged in recent decades. Here, we report on measurements of the BC concentration in snow samples from 28 sites across a transect of about 2,000 km from the northern tip of Antarctica (62°S) to the southern Ellsworth Mountains (79°S). Our surveys show that BC content in snow surrounding research facilities and popular shore tourist-landing sites is considerably above background levels measured elsewhere in the continent. The resulting radiative forcing is accelerating snow melting and shrinking the snowpack on BC-impacted areas on the Antarctic Peninsula and associated archipelagos by up to 23 mm water equivalent (w.e.) every summer.

Context. Glitches are sudden increases in the rotation rate ν of neutron stars, which are thought to be driven by the neutron superfluid inside the star. The Vela pulsar presents a comparatively high rate of glitches, with 21 events reported since observations began in 1968. These are amongst the largest known glitches (17 of them have sizes Δ ν / ν ≥ 10 −6 ) and exhibit very similar characteristics. This similarity, combined with the regularity with which large glitches occur, has turned Vela into an archetype of this type of glitching behaviour. The properties of its smallest glitches, on the other hand, are not clearly established. Aims. We explore the population of small-amplitude, rapid rotational changes in the Vela pulsar and determine the rate of occurrence and sizes of its smallest glitches. This will help advance our understanding of the actual distribution of glitch sizes and inter-glitch waiting times in this pulsar, which has implications for theoretical models of the glitch mechanism. Methods. High-cadence observations of the Vela pulsar were taken between 1981 and 2005 at the Mount Pleasant Radio Observatory. An automated systematic search was carried out that investigated whether a significant change of spin frequency ν and/or the spin-down rate ν ̇ takes place at any given time. Results. We find two glitches that have not been reported before, with respective sizes Δ ν / ν of (5.55 ± 0.03) × 10 −9 and (38 ± 4) × 10 −9 . The latter is followed by an exponential-like recovery with a characteristic timescale of 31 d. In addition to these two glitch events, our study reveals numerous events of all possible signatures (i.e. combinations of Δ ν and Δ ν ̇ signs), all of them small with |Δ ν |/ ν < 10 −9 , which contribute to the Vela timing noise. Conclusions. The Vela pulsar presents an under-abundance of small glitches compared to many other glitching pulsars, which appears genuine and not a result of observational biases. In addition to typical glitches, the smooth spin-down of the pulsar is also affected by an almost continuous activity that can be partially characterised by small step-like changes in ν , ν ̇ or both. Simulations indicate that a continuous wandering of the rotational phase, following a red spectrum, could mimic such step-like changes in the timing residuals.

There is a vast amount of evidence that suggests that the geomagnetic tail is like a turbulent wake behind an obstacle. Large-scale vortices in the wake are able to generate turbulent transport that takes place both along the plasma sheet, in the X and Y directions, and across the plasma sheet, in the Z direction. Thus, turbulent fluctuations in all directions should be taken into consideration when analyzing plasma transport in the plasma sheet, and stability of the plasma sheet configurations. In this review, we summarize and discuss the main results of large and middle scale magnetospheric turbulence yielded by data analysis and modeling. We also identify changes in the description of the magnetospheric dynamics connected with the existence of turbulent fluctuations in the tail.

We analyzed the problems of formation of the outer radiation belt (ORB) taking into consideration the latest changes in our understanding of the high-latitude magnetospheric topology. This includes strong evidence that the auroral oval maps to the outer part of the ring current, meanwhile the ORB polar boundary maps inside the auroral oval. Our analysis also includes the variation of the plasma pressure distribution and the time of the acceleration of relativistic electrons during geomagnetic storm. It is shown that the maximum of ORB is formed after the geomagnetic storm in the region of plasma pressure maximum. The position of this maximum agrees with the prediction of the ORB formation theory based on the analysis of ring current development during storm. We emphasize the role of adiabatic processes in the ORB dynamics and the importance of the substorm injections during storm recovery phase for the formation of enhanced fluxes of ORB electrons after the storm.

The adiabatic and non-adiabatic behavior of relativistic electrons in the outer radiation belt during the 1 June 2013 geomagnetic storm is studied using data from the Van Allen Probes and THEMIS missions. Analysis of the evolution of the plasma pressure shows that the pressure increased by one order of magnitude during the storm reaching a maximum value towards the end or slightly after the main phase of the storm. At the same time, the location of the maximum pressure moved towards the Earth, reaching the closest distance at L∼3.7. Relativistic electron fluxes show that the location of the peak fluxes also move closer to the Earth reaching the same L as the maximum of plasma pressure. In order to study whether the adiabatic mechanisms are relevant to explain the behavior of relativistic electrons, we analyzed the electron fluxes in the energy range from 1.8 to 4.2 MeV and found that the electron spectra fits well to a power law function. For a fixed L−shell, the power law index is conserved during the pre-storm time, increases during the main phase, and presents little variation again during the recovery phase, but the power law index calculated during the recovery phase is larger than during pre-storm phase. A strong depletion of electron fluxes during the main phase of the storm is also measured, with fluxes returning to the pre-storm level afterwards. The conservation of the slope of the electron spectra during a long time can be considered as an evidence of a dominant contribution of adiabatic processes, as it is difficult to explain this effect as other processes such acceleration and losses of relativistic electrons. An increase of the power law index towards the end or right after the main phase of the storm can be related to the increase of the losses with the electron energy, and/or to the processes of thermalization (relaxation) of the electron distribution functions.