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We report new estimates of the intensity of the geomagnetic field strength for the Permian–Triassic boundary. Amid predominantly low virtual dipole moment values for that time in the Global Paleointensity Database, episodes of increased VDM up to 8.9 × 1022 Am2 were recorded in the sections of the trap formation of the Kuznetsk depression, which do not conform to the Mesozoic Dipole Low concept. Analysis of data on changes in the value of the virtual dipole moment during the formation of the Siberian Large Igneous Province within the framework of modern magnetostratigraphic correlations indicates a persistently weak geomagnetic field only at the initial stage, when most of its Norilsk area was formed. A change in the geomagnetic mode is noted after ~800 thousand years at the level of subchron LT1n.1r (251.2–251.1 Ma) of the General Magnetostratigraphic Scale and was recorded in the basaltic andesite lava sheets of the Kuznetsk area. Low virtual dipole moment values from this time correspond to episodes of reversals, while the overall intensity was on average only slightly lower than today. Thus, the drop in paleointensity at the very beginning of the Triassic period was not caused by a major long-term change in the geodynamo, but was short-term and related to plume activity. [ABSTRACT FROM AUTHOR]

This paper is an exploration of how massively distributed femtosatellite networks can be implemented in space missions aimed at modelling the space environment for variables that show both time and space dependence. A theory of distributed sensing for space-time deconvolution is presented and performance parameters for system evaluation are described. Measurement of the magnetic field in low Earth orbit, in the presence of field perturbations, is selected as a case study for demonstrating the concept in simulation. A femtosatellite swarm, designed for the simulated space environment, shows the capability of space-time deconvolution in sensing. From the simulated mission, challenges in the design and deployment of free-flying sensor swarms, especially in the femtosatellite mass range, are identified and discussed. • An exploration of femtosatellite applications for solving real problems in space research. • Data analysis for massively distributed in-parallel sensing for time and space deconvolution with femtosatellites. • Femtosatellite mission design and simulation for distributed sensing applications. [ABSTRACT FROM AUTHOR]

The climate of the upper atmosphere, including the mesosphere, thermosphere and ionosphere, is changing. As data records are much more limited than in the lower atmosphere and solar variability becomes increasingly dominant at higher altitudes, accurate trend detection and attribution is not straightforward. Nonetheless, observations reliably indicate that, on average, the mesosphere has been cooling, the density in the thermosphere has been decreasing, and ionospheric layers have been shifting down. These global mean changes can be largely attributed to the increase in CO 2 concentration, which causes cooling and thermal contraction in the middle and upper atmosphere. The decline in thermosphere density is particularly relevant from a practical viewpoint, as this reduces atmospheric drag and thereby increases orbital lifetimes and the build-up of space debris. Long-term changes in the ionosphere can have further practical implications and are not only driven by the increase in CO 2 concentration, but also by changes in the Earth's magnetic field. The empirical models that are mostly used to inform applications in industry on the state of the upper atmosphere, as well as being widely used in science, do not yet properly account for long-term trends in the mesosphere, thermosphere and ionosphere. This is problematic when long-term future projections are needed or models rely strongly on older data. This review provides an overview of the main evidence of long-term trends observed in the mesosphere, thermosphere and ionosphere, together with the latest insights on what causes these trends. It is hoped that this may serve as a starting point to include long-term trends in (semi-) empirical models to benefit all users of these models. We also offer some thoughts on how this could be approached. [ABSTRACT FROM AUTHOR]

In spacecraft mission planning and operation, the attitude determination and control subsystem (ADCS) of a satellite provides information about the orientation of the satellite in the inertial reference frame. Furthermore, this subsystem produces the control actions required to adjust the orientation of the satellite, especially in the low-Earth orbit (LEO) regime. This paper focuses on the satellite's three-axis attitude control problem within the context of active and passive control, which includes detumbling control, pointing control, magnetic control, and attitude stabilization after solar panel wing deployment using magnetorquers as the primary actuators. The objective is to stabilize and reduce the angular rate while orienting the satellite to the desired attitude. The proposed satellite attitude control system (ACS) strategies are designed, developed, characterized, and verified. These strategies encompass the B-dot control algorithm for detumbling control along with pointing control and attitude stabilization after solar panel wing deployment. hardware-in-the-loop simulation (HiLs) tests are conducted to assess the performance of the satellite magnetorquer-based ACS in the presence of noise. These tests involve a relative Earth's magnetic field (EMF) generator in conjunction with SGP-4-based satellite orbital propagator high-level control software. Additionally, cascade proportional-integral-derivative (PID) and state-dependent Riccati equation (SDRE) controllers are implemented to generate sufficient torque using three-axis magnetorquers on a frictionless air-bearing platform. The platform is balanced to closely simulate the dynamic motion of a spacecraft in space. The testing includes a single initial condition and three inertia conditions for stabilization after solar panel wing deployment. Finally, the effectiveness of the cosimulation as a primary experiment through an integrated HiLs process is validated. This comprehensive approach confirms the control system's performance and its ability to meet mission requirements. [ABSTRACT FROM AUTHOR]

The Himalayas are a region of geomagnetic importance, as they impact the geomagnetic field of Earth and space weather, as it is one of the largest mountain belts in the world. Due to its huge mass, it may influence the dynamics of the Earth's core, the primary source of the geomagnetic field. In Indian longitudes, the mean location of the solar quiet (Sq) focus lies in latitudes closer to the Hanle region. Therefore, monitoring the magnetic field in the Hanle region is important. Ideally, a zero magnetic gradient or low magnetic gradient of the order of a few nT/m or less is preferred; this low gradient helps reduce the effects of local magnetic variations. Hence, to establish a continuous geomagnetic observation setup, a magnetic survey was conducted at Hanle, Ladakh, to identify the location of the low magnetic gradient. From the magnetic survey, the eastern part of the selected hillock was identified that has the least magnetic gradient. After checking other logistics, the chosen site is suitable for setting magnetic field observations. The proposed magnetic observatory at Hanle will be useful for studies related to unusual space weather phenomena, such as the citing of Auroras (of 22–23 April 2023 and 10–11 May 2024) in the Ladakh region, geomagnetic field monitoring in low-mid transitional regions, or magnetic exploration. [ABSTRACT FROM AUTHOR]

In this work, we present ArchaeoPyDating, a new version of the archaeo_dating Matlab software used for archaeomagnetic dating. This updated version introduces a transition from the original Matlab code to Python, enabling the software to be presented as an online tool. By offering a web‐based interface, ArchaeoPyDating eliminates the need for licenses, program installations, or programming expertise, making it widely accessible to users through various devices and browsers. This enhanced accessibility holds great potential for popularizing the archaeomagnetic dating method. This study presents both the new online version of the tool and a Python module that encompasses all the essential classes and functions required for conducting archaeomagnetic dating in a command‐line environment, which can be useful for advanced users. [ABSTRACT FROM AUTHOR]

Geomagnetic field models covering past millennia rely on two main data sources: archaeomagnetic data, that provide snapshots of the geomagnetic field at specific locations, and sediment records, that deliver time series of the geomagnetic field from individual cores. The limited temporal and spatial global coverage with archaeomagnetic data necessitates use of sediment data, especially when models go further back in time. However, the accurate preprocessing and interpretation of sediment data is crucial. Unlike archaeomagnetic data, sediment data does not provide absolute values for intensities and declinations; instead, it represents relative variations. The detrital remanent magnetization (DRM) of sediment records is influenced by various depositional (dDRM) effects that can result in inclination shallowing, as well as post‐depositional (pDRM) processes that cause a delayed and smoothed signal. To address the distortion associated with the pDRM effects, a novel class of flexible parameterized lock‐in functions has been proposed. These lock‐in functions involve four parameters, which are estimated using a Bayesian modeling technique and archaeomagnetic data. By extending the space of hyperparameters to include the calibration factor for intensities, the declination offsets and the inclination shallowing factor, we present a fully Bayesian preprocessing method for sediment records in form of a Python package, called sedprep. By applying the estimated parameters to the raw sediment data sedprep is able to provide a calibrated and preprocessed palaeomagnetic record. Plain Language Summary: Our research introduces a new Python package called sedprep that helps scientists better understand ancient magnetic field records from ocean and lake sediments. Unlike other sources like lava flows or historical artifacts, which offer snapshots of the magnetic field at specific points in time, sediment records provide a continuous history that can span thousands to millions of years. However, interpreting the magnetic signal in sediments can be challenging due to various natural processes that occur during and after deposition or due to the way records are extracted. To correct the resulting inaccuracies, we present a method that accounts for various influencing factors and adjusts the sediment record. This correction process involves statistical techniques and independent magnetic information derived from archaeomagnetic data. We've tested sedprep with both synthetic data and real‐world examples, showing that it can effectively reconstruct the main characteristics of the Earth's magnetic field from sediment records. The next steps involve applying sedprep to more datasets to validate its effectiveness and to help improve global models of the Earth's magnetic field. Key Points: We present sedprep, a Python package that can be used to preprocess palaeomagnetic sediment recordssedprep estimates declination offsets, RPI calibration, inclination shallowing factor, and lock‐in function parameters simultaneouslyThe final step applies the estimated parameters to provide the calibrated and corrected palaeomagnetic signal [ABSTRACT FROM AUTHOR]

Large geomagnetic disturbances are fairly rare events, even near the top of the solar cycle. These are mostly caused by particle radiation from the Sun. The flow of these particles is called solar wind. The terrestrial magnetosphere and ionosphere create magneto-hydro-dynamic waves that produce an increase in the magnetic field on the Earth's surface. The recording of the geomagnetic field is carried out in geomagnetic observatories and with the help of satellites. Magnetic observatories are permanent measuring stations that monitor geomagnetic field variations with very high precision both in time and in amplitude. Several calculation methods were used to quantify these variations, resulting in various indices of magnetic activity. They are calculated either at the planetary level or for specific areas on Earth (equatorial indices (Ae), daily indices (Ap), planetary indices (Kp), geomagnetic activity index (Dst)). In the present work, the geomagnetic storm produced on March 24, 2024 was analysed. There are situations where the different way of reporting the geomagnetic indices (Dst and Kp) can lead to the classification of the same phenomenon in two different categories (average storm after Dst and strong storm after Kp). [ABSTRACT FROM AUTHOR]

In-situ cosmogenic 10Be (and 26Al) concentrations in alluvial sediments provide a spatially averaged signal of the erosion rate of the catchment area. Catchmentwide erosion rates reflect the production rate of the entire basin, and their calculation requires knowledge of the complete production rate model. Available calculators determine production rates on a pixel-based approach and achieve computational efficiency by relying on a scaling method that ignores geomagnetic field strength variations. Here we introduce a new python-based tool that determines erosion rates based on the hypsometry of the catchment. The method relies on the fact that production rates are much more sensitive to changes in elevation than latitude. Our tool has two main advantages: (1) computation time is short (<30 seconds) and independent of the scaling method; there is no need to neglect magnetic field variations, and (2) because production rate scaling is performed by a widely used online calculator, the results are fully comparable to exposure ages or point-based erosion rates determined with the same calculator; future updates to production rate scaling are immediately effective for catchmentwide erosion rate calculation. We demonstrate in two case studies that (1) for similar scaling methods, our calculator reproduces pixel-based results within a few percent, and (2) erosion rates determined with different scaling methods may differ by >20%, differences can vary systematically with erosion rate, and using a time-constant scaling method may result in a bias in the interpretation of catchmentwide erosion rates. [ABSTRACT FROM AUTHOR]

Ground magnetic field measurements are an important tool to determine the strength of space weather events in the terrestrial environment on local and global scales. For that purpose, geomagnetic baselines play a vital role as they describe typical quiet variations within geomagnetic data which allows the successive isolation of magnetic storm contributions. This work introduces an operational baseline derivation method to accurately assess then replace the amplitude of space weather events within high‐quality ground magnetic field measurements from magnetic observatories located in mid‐latitudes. A two‐step approach first identifies storm and disturbance intervals within the magnetic signal. Quiet variations, consistent with pre‐ and post‐disturbance periods, are then used to replace the signal during the identified intervals. The final baseline is validated through comparisons with existing methods and through demonstration during moderate and strong space weather events at 13 globally distributed observatories, demonstrating its ability to track quiet variations accurately while maintaining them during disturbances. This supports the application of the introduced baseline for geomagnetic field description and new magnetic index derivation for space weather event characterization with high spatio‐temporal resolution. As the method is deployable in near real‐time, it is suitable for operational environments. Plain Language Summary: This research article is about a new method to improve the measurements of space weather effects on Earth's magnetic field. Space weather can cause significant disturbances in Earth's magnetic field, which are measureable from ground magnetic observatories. The new method helps remove these disturbances from the ground magnetic field measurements by describing the quiet magnetic field variations. This is important for understanding space weather and its effects. The introduced method works in two steps. First, it identifies periods of space weather activity in the measurements. Then, it replaces those periods with data from calmer times before or after the event. We show that this method works well for observatories in mid‐latitude regions and can be deployed in near real‐time making it useable in operational environments. Key Points: A geomagnetic baseline method is proposed that can be deployed in operational (near‐) real‐time environmentsAn algorithm that identifies magnetic disturbances within geomagnetic field measurements is introducedPossible replacements for magnetic quiet variations during storm and disturbance periods are elaborated [ABSTRACT FROM AUTHOR]

This study investigates the Brazilian low‐latitude ionospheric response to CIR/HSS‐driven geomagnetic storms during the declining phase of solar cycle 24, from 2016 to 2017. In this period the geomagnetic storms were mostly moderate, SymHmin ≈ −72 nT, AEmax ≈ 1580 nT, Vswmax ≈ 690 km/s and lasted, on average, for 6 days. We analyze the variations in Vertical Total Electron Content (VTEC) at three representative regions: bele, over the equatorial region; boav and cuib, at the northern and southern crests of the Equatorial Ionization Anomaly. Our findings reveal the role of High‐Speed Solar Wind Streams and Corotating Interaction Region—driven geomagnetic storms. The VTEC intensifications were up to 30 TECu, during the daytime and nighttime. Additionally, three categories of nighttime enhancements were observed and analyzed with distinct characteristics and levels of pre‐reversal strengthening; Depletions up to 20 TECu also occurred during the day and nighttime. The delay between the storm commencement and the positive and negative variations were, on average, 7 and 20 hours, respectively. We discuss the Prompt Penetration Electric Fields and Disturbance Dynamo Electric Fields following the magnetic reconnection between Earth's and interplanetary magnetic field, using observational data and modeling. Furthermore, this study presents catalogs of low‐latitude ionospheric storms, providing detailed information for space weather applications and ionospheric modeling. Plain Language Summary: This study examines the impact of solar wind on the low‐latitude ionosphere, in Brazilian longitudinal sector, during the descending phase of the SC 24, 2016/2017. Specifically, we focused on High‐Speed Solar wind Streams (HSS) and Corotating Interaction Regions (CIRs) that can cause disturbances in the Earth's magnetic field, leading to weak‐to‐moderate geomagnetic storms. Our findings show that these disturbances can affect the low‐latitude ionosphere for several days. By analyzing the variations in the Vertical Total Electron Content (VTEC), we found that remarkable increases occur during the recovery phase of these storms, observed at the crests of the EIA. This study provides new insights into the effects of the solar wind on the Earth's atmosphere during moderate solar activity which can be of interest for space weather applications. Key Points: Statistical study on the low‐latitude Vertical Total Electron Content in Brazilian longitudinal sector during the declining phase of SC 24 and Catalogs with the main resultsLow latitude daytime and nighttime ionospheric variations were observed up to 30 TECu and −20 TECuEffects of prompt penetration electric fields and disturbance dynamo electric fields in the Brazilian low latitude ionosphere: three case studies [ABSTRACT FROM AUTHOR]

The document provides abstracts for upcoming conferences in India and Italy organized by Biju Longhinos and Valentino Straser, respectively. It discusses theoretical frameworks for understanding Earth's energy budget and the effects of solar activity on seismicity and weather patterns. The text explores correlations between solar phenomena, earthquakes, hurricanes, and tornado outbreaks, suggesting potential electromagnetic and tectonic modulations. The research aims to investigate the complex interactions between space weather, seismic activity, and extreme weather events, highlighting the need for further study in these interconnected fields. [Extracted from the article]

On 10 May 2024, a super geomagnetic storm occurred with a minimum Dst index of −412 nT. This study investigates the behavior of the ionospheric radial current (IRC) during the main phase of this storm using data from Swarm A and simulations from the Thermosphere‐Ionosphere Electrodynamics General Circulation Model (TIEGCM). At dawn, the IRC exhibits distinct temporal variations: a strong outward flow of 14 nA/m2 between 18:00 and 20:00 UT and an inward flow of −15 nA/m2 by 24:00 UT. At dusk, the IRC starts with an inward value of −6 nA/m2 and rapidly reverses to an outward flow peaking at 15 nA/m2 between 22:00 and 24:00 UT. The dawn‐dusk asymmetry of the IRC is primarily influenced by the merging electric field (Em). Increasing Em penetrates to low latitudes, establishing an eastward (dusk) or westward (dawn) electric field and enhancing the outward (dusk) or inward (dawn) IRC through meridional Hall currents. Model results indicate that the strong polarity changes in dawn IRC are linked to local disturbed zonal winds (Δuy ${{\Delta }u}_{y}$). Which are eastward at dawn and westward at other magnetic local times (MLT). The eastward/westward Δuy ${{\Delta }u}_{y}$ generate outward/inward F‐layer dynamo currents, driving the disturbed vertical electric field (ΔEz ${{\Delta }E}_{z}$) in opposite direction. The significant outward reversal of dusk ∆IRC could be attribute to the rapid enhancement of disturbed Pedersen conductivity (Δσp ${{\Delta }\sigma }_{p}$). Due to nonzero geomagnetic declination, eastward/westward Δuy ${{\Delta }u}_{y}$ corresponds to an increase/decrease in Δσp ${{\Delta }\sigma }_{p}$. Key Points: Ionospheric radial current (IRC) has an extreme response of approximately 15 nA/m2 to the super stormThe increase of Em can enhance the outward/inward IRC at dawn/duskΔuy ${{\Delta }u}_{y}$ (Δσp ${{\Delta }\sigma }_{p}$) is key in the polarity changes of IRC at dawn (dusk) [ABSTRACT FROM AUTHOR]

The cold plasma density can significantly alter the rate of diffusion of radiation belt electrons by chorus waves within the magnetosphere, and the range of energies at which diffusion is effective. We describe a coupled density and radiation belt model based on the British Antarctic Survey Radiation Belt Model that uses spatially and temporally varying values of fpe/fce ${f}_{pe}/{f}_{ce}$ to drive a statistical model of electron diffusion due to chorus waves. We demonstrate that this approach of including the variance in fpe/fce ${f}_{pe}/{f}_{ce}$ recreates the acceleration of electrons up to MeV energies better than other previous approaches to including fpe/fce ${f}_{pe}/{f}_{ce}$. Plain Language Summary: The density of low energy charged particles trapped in Earth's magnetic field can influence how higher energy trapped electrons are affected by natural radio waves within the magnetic field. We describe a modification of the British Antarctic Survey Radiation Belt Model that includes a model of density that varies in both time and space. These density values are used to drive a statistical model of electron scattering due to chorus waves. We demonstrate that including the variance of density in the model recreates the acceleration of electrons up to ultra‐relativistic energies better than other previous approaches to accounting for the low energy charged particle density. Key Points: More realistic information about the plasma density leads to better recreations of multi‐MeV electron flux enhancements in a diffusion modelChorus waves can directly accelerate electrons to multi‐MeV energies at L* = 4 when the plasma density is low, without radial diffusionThe Van Allen Probes fpe/fce ${f}_{pe}/{f}_{ce}$ measurements are biased away from values less than 2.5 [ABSTRACT FROM AUTHOR]

In this paper, we develop a climatology model of the ionospheric electric field and potential at low and middle latitudes on quiet time, utilizing plasma drift observed from the ROCSAT‐1 satellite. The meridional/vertical and zonal E × B drifts are transformed to the electric fields using modified Apex coordinates under the real geomagnetic field model. The electric field data are adjusted to different solar levels through bilinear fitting, and organized into seasonal, longitudinal, latitudinal bins. The fully normalized associated Legendre functions are chosen as the fitting basis modes. Our model can effectively describe the latitudinal dependence of the electrodynamics parameters cover equatorward of 35° magnetic latitude. The fitted drifts hold the fundamental characteristics of the results observed prior to fitting. The model potential can well shows the typical morphological characteristics that are in great agreement with prior research findings. Furthermore, the potential variations exhibit distinct seasonal, solar flux, and UT dependence under moderate and high solar flux conditions. Within the framework of this model, the potential, electric field, and drift can be mutually converted while maintaining self‐consistency. Plain Language Summary: Traditional ionospheric plasma drift models mostly cover the equatorial region and focus on vertical drift, limited by the observation conditions and the errors in measurement. We produce a new global‐scale ionospheric electrodynamics model, by combining a large number of drift data observed from low‐orbit satellites. The plasma drift has a good corresponding relationship with the electric field on geomagnetically quiet time. Assuming equipotential geomagnetic field lines allows for the doubling of electric field sample quantity with the unit of volt per degree. The ionosphere satisfies the quasi‐steady state assumption, which allows potential to be expressed as the Laplace equation. Therefore, we can fit the electric through the orthogonal functions, to get the potential global distribution on the reference plane. As an important parameter output from the ionospheric theoretical model, the potential can also serve as an input to run the model. Our model can realize mutual conversion based on the transform among plasma drift, electric field, and potential in an orthogonal framework. The model captures original characteristics of the drift observations. The results are in great agreement with the current potential models, and could show more details on the spatial distribution. Our framework will allow for the inclusion of more observations and remain updated. Key Points: An empirical model of the ionospheric electric field and potential on quiet times in the low and middle latitudes has been developed using observations from the ROCSAT‐1 satelliteOur model effectively captures the dependence of ionospheric electrodynamics parameters on solar flux, season, Universal Time, longitude, and latitudeThe framework allows for the conversion of drift velocity, electric field, and potential into one another while ensuring good smoothness and stability, while also maintaining self‐consistency [ABSTRACT FROM AUTHOR]

Magnetic reconnection has been commonly reported between the solar wind IMF and the magnetic field of Earth and other planets. A similar phenomenon is expected between Jupiter's magnetosphere and Ganymede's mini magnetosphere inside the Jovian magnetosphere. This article is the first report of a reconnection event in the tail region of Ganymede. We present compelling evidence that Juno flew in close proximity to an X‐line, that was not within the tail current sheet, but rather in the turbulent wake area of Ganymede. We report the observation of distinctive electron Bernstein mode waves with unique characteristics particular to a separatrix region of the reconnection site. We detect a clear reversal of a magnetic field component. Electron densities and pitch angle distributions also indicate that Juno possibly traversed the inflow, and outflow region surrounding the separatrix region. Finally, from the time sequence of the observations by the different instruments on Juno, we reconstruct a likely trajectory of Juno around the reconnection site. Key Points: Juno passed near a magnetic reconnection X‐line in Ganymede's downstream region on 7 June 2021Juno Waves observations provide a positive indication of being in the reconnection separatrix siteJuno JADE electron measurements show the flux increase and pitch angle distributions expected in a separatrix region [ABSTRACT FROM AUTHOR]

We present multiple derivations of the Total Radiation Belt Electron Content (TRBEC), an indicator of the global number of electrons that instantaneously occupy the radiation belts. Derived from electron flux measurements, the TRBEC reduces the spatial information into a scalar quantity that concisely describes global aspects of the system. This index provides a simple, global, and long‐term assessment of the radiation belts that enables systematic analysis. In this work, we examine the TRBEC using the adiabatic invariants of μ,K,L∗ $\left(\mu ,K,{L}^{\ast }\right)$ which has been used in previous articles as this coordinate system removes reversible adiabatic effects. We then introduce a new expression to compute the TRBEC using the non‐adiabatic coordinates of E,αeq,L∗ $\left(E,{\alpha }_{eq},{L}^{\ast }\right)$, relevant in the contexts of energetic electron precipitation, chorus, and hiss scattering where adiabatic invariant quantities are no longer conserved. From both expressions of the TRBEC we demonstrate that an erroneous factor of (2π)3 ${(2\pi)}^{3}$ that appeared in previous works using the adiabatic derivation led to an overestimate of the reported electron populations. In addition, we quantify electron loss in the outer radiation belt 3.5

In the scientific field of collisionless shocks, interplanetary space comprises a critical natural laboratory allowing the study of processes at spatial scales which are impossible to recreate in laboratories on Earth. Despite decades of research, key questions in the dynamics of collisionless shocks including energy transport and exchange remain unresolved due to instrumental limitations. With the return of humanity to the Moon and the upcoming construction of the Lunar Platform: Gateway (LOP‐G) space station, the possibility arises to study the pristine solar wind in unprecedented detail, with the space station potentially enabling significant power capacity and data rates which would be challenging to achieve on smaller unmanned spacecraft. The space station's location in a lunar halo orbit allows the study of the solar wind away from the contaminating influence of the terrestrial bow shock. Here we propose to utilize nitrogen‐vacancy (NV) diamond technology to combine magnetometer, temperature and plasma density measurements into a single instrument which can sample kHz‐range magnetic field with sensitivities on the order of <1e−5 nT, while also sounding the local plasma density and temperature. These capabilities will generate datasets which will contribute significantly to shock science, helping answer key outstanding questions in the field. Simultaneously, these observations will improve understanding of space weather dynamics, contribute to cross‐calibrating complementary missions, and probe the lunar exosphere. With the paucity of long‐term, high‐cadence, high‐sensitivity pristine solar wind datasets, the Diamond Experiment In the MagnetOSphere (DEIMOS) will fill a key need for the solar wind and collisionless shocks community. Plain Language Summary: Studying plasma in space allows us to observe some important effects which are too big to be reproduced in a laboratory on Earth. For this reason, studying the solar wind that is created by events such as solar flares, as it passes by our planet, can help our understanding of plasma physics, which in turn is valuable for controlled nuclear fusion and other plasma applications. In order to study the solar wind correctly, the spacecraft needs to be far away from the Earth so the solar wind plasma is not distorted by interaction with the Earth's magnetic field. The Moon is a perfect place, since it is far away from Earth but also large enough that a stable orbit around it can be established. Here we propose to deploy a new technology—a highly integrated nitrogen‐vacancy diamond magnetic field sensor—on the future Lunar Gateway space station, where it can collect large amounts of high‐resolution data to better understand solar wind turbulence. The sensor can also improve space weather model accuracy, support other space missions, and study the Moon's thin plasma atmosphere. Key Points: Nitrogen‐vacancy (NV) diamond magnetometers enable high cadence rates of magnetic field, temperature and densityOn Gateway, this will enable pristine solar wind studies of electron‐range plasma turbulence and non‐local shock‐related instabilitiesIt will also quantify space weather model accuracy, support other solar wind and magnetosphere missions, and probe lunar plasma [ABSTRACT FROM AUTHOR]

Magnetically connected observations of particle distributions and luminosity from the Reimei spacecraft are used to examine energy transport and conversion occurring above a discrete auroral arc. By combining imaging and in situ measurements it is shown how transverse electromagnetic and kinetic energy fluxes measured along the spacecraft trajectory converge across geomagnetic field‐lines into the acceleration region. It is shown how cross‐field energy transport is facilitated by the formation of vortices along the length of the arc. From an integration over the vertical extent of the acceleration region it is shown that the transverse and field‐aligned flow of energy into the arc locally supports the dissipation needed to power the electron acceleration observed. Estimates of gradients in electromagnetic and kinetic energy flows show how field‐aligned electron energization in the acceleration region is supported by the divergence of Poynting flux along and across the background magnetic field. Key Points: The contributions to energy transport above a bright discrete auroral arc are estimatedAdvection in vortices is estimated to locally transport energy through the acceleration region at rates comparable to incoming Poynting fluxIt is shown how estimates for the divergence of Poynting flux match the observed rate of electron energization [ABSTRACT FROM AUTHOR]

A Comprehensive Inner Magnetosphere‐Ionosphere (CIMI) model has been developed to study the dynamics of the cold plasmasphere and the energetic plasmas in the inner magnetosphere, as well as their couplings with each other and with the ionosphere. The CIMI model is able to predict the cold plasma density and energetic electron and ion fluxes in geospace. Furthermore, CIMI is capable of predicting the Region 2 currents, penetration electric field, electron and ion precipitation and magnetospheric heat flux into the ionosphere. The CIMI model includes a realistic magnetic field configuration with a combination of an internal field and an external field imposed by the interaction of the solar wind with the magnetosphere. The internal field has previously been assumed to be a dipole. Recently, the International Geomagnetic Reference Field (IGRF) has been implemented. This new capability enables studies of north‐south and longitudinal dependences in particle precipitation and heat flux, as well as the corresponding asymmetries in ionospheric and thermospheric responses. In this paper, we will briefly review the CIMI equations and model output. Then we will describe the new implementation of the IGRF model into CIMI and how to estimate the north‐south asymmetry in precipitating fluxes from the differences in field strength between magnetic conjugate points. The inclusion of a realistic internal field leads CIMI into a better position to couple with sophisticated ionosphere‐thermosphere models, most of which are using the IGRF model. Key Points: The CIMI model has been improved by implementing the IGRF model as an alternative to a dipole to represent the earth's internal fieldWith the IGRF internal field, strong north‐south asymmetries in particle precipitation and heat flux into the ionosphere are reproducedNorth‐south asymmetry in particle precipitation can be estimated by the corresponding loss cone asymmetry [ABSTRACT FROM AUTHOR]

Interpreting the paleomagnetic records of altered rocks, especially those from Earth's earliest history, is complicated by metamorphic overprints and recrystallization of ferromagnetic minerals. However, these records may be as valuable as a primary signal if the timing and mechanism of alteration‐related remagnetizations can be ascertained. We illustrate the success of this approach in the case of seafloor hydrothermal alteration by integrating simple rock magnetic and magnetic microscopy data with petrography, hyperspectral imagery, aeromagnetic surveys, field mapping, and geochronology of Paleoarchean basalts from North Pole Dome located in the East Pilbara Craton, Western Australia. We identify 12 hydrothermal episodes during the deposition of the stratigraphy between ∼3490 and 3350 Ma. These episodes produced stratabound zones of hydrothermal alteration with predictable facies successions of mineral assemblages reflecting sub‐seafloor gradients in fluid temperature, pH, composition, and water/rock ratios. Rock magnetic data and magnetic microscopy pinpoint the secondary ferromagnetic minerals within each alteration assemblage, revealing a specific single‐domain magnetite population within leucoxenes (titanite and anatase after primary titanomagnetites) that always accompanies low‐water/rock alteration in fluids buffered to pH equilibrium with the host basalts. Highly uniform magnetic properties indicate that once formed, these magnetites remain unchanged upon further exposure to rock buffered fluids, stabilizing them against later alteration events and making them durable paleofield recorders. The altered basalts hosting this magnetite have unique and consistent appearances, mineralogy, IR absorption features, aeromagnetic signatures, and magnetic properties across all hydrothermal systems studied here, highlighting how integrating these data sets can identify and interpret this alteration style in future paleomagnetic investigations. Plain Language Summary: Paleomagnetists interpret the magnetic signals preserved in rocks to understand plate tectonics and the Earth's magnetic field in the deep past. However, rocks can get altered via heat, pressure, or chemical reactions, which also alter these magnetic signals. The aim of this study is to demonstrate that one type of alteration—chemical alteration of rocks as they marinate in circulating hot water within seafloor hydrothermal systems—modifies the magnetic signals of rocks in order to use them for future paleomagnetic studies. Using airborne infrared imaging, magnetic field mapping, field observations, and radiometric dating, we demonstrate that an area of Western Australia called North Pole Dome experienced a dozen seafloor hydrothermal alteration events over 3 billion years ago. We then use magnetic measurements and mineralogical observations to document how these hydrothermal systems altered the magnetic signals in their host rocks. These analyses reveal a recognizable population of altered rocks that can preserve paleomagnetic signals related to hydrothermal alteration. This is because the alteration results in the growth of very fine‐grained magnetite with all the necessary characteristics to reliably and durably hold onto magnetic signals over geologic time. Key Points: Field mapping, remote sensing, and petrographic data identify 12 seafloor hydrothermal episodes in an Archean volcanic successionMagnetic and mineralogical characteristics of the basalts predictably co‐vary with alteration facies across all hydrothermal systemsWe establish a geologic, chronological, and petrographic framework for identifying seafloor hydrothermal remagnetization in basalts [ABSTRACT FROM AUTHOR]

Continuous reconstructions of past variations of the Earth's magnetic field are based mainly on paleomagnetic and cosmogenic 10Be records in marine sediments. In both cases, the recording mechanisms can be affected by environmental processes. Climatic overprints are only partially removed by normalization procedures, so that stacking is used to further remove site‐specific effects. Regionally or globally correlated artifacts, however, cannot be removed by stacking. Here we present a modified approach where geomagnetic records are complemented by environmental proxies representing processes that might affect the field recording mechanism. Geomagnetic and environmental records are jointly processed with principal component analysis to obtain a set of components supposed to represent true variations of the geomagnetic field and climatic overprints, respectively. After discussing the theoretical background of this new approach and its underlying assumptions, a practical example is presented, using a worst‐case scenario based on a single 10Be record from the North Atlantic with strong climatic overprints, covering the last 600 ka. The first two principal components, which represent the modulation of 10Be by global climatic variations and by the geomagnetic field, respectively, explain 66.3% of the signal variance. Comparison of the geomagnetic principal component with global relative paleointensity stacks shows that the original climatic overprint can be reduced by a factor of 2, outperforming a 10Be/9Be stack obtained from two sites with little glacial‐interglacial variability. The proposed method for removing climatic overprints can be applied to multiple sites more efficiently than conventional stacking. Plain Language Summary: Continuous records of the Earth's magnetic field rely on measurements of magnetic minerals or cosmogenic isotopes in sediments. Both types of records are also sensitive to environmental conditions and are thus affected by past climatic variations. These unwanted climatic overprints are difficult to remove: one strategy consists in stacking records from different sites; however, regionally or globally correlated artifacts cannot be completely removed by this technique. Here we present a new method for separating the geomagnetic signal from unwanted climatic overprint, which is based on the principal component analysis (PCA). The efficiency of this new method is tested with a worst‐case example based on a single site located in the North Atlantic, which is characterized by strong glacial‐interglacial variability. The first two principal components obtained from PCA represent the modulation of 10Be by global climatic variations and by the geomagnetic field, respectively. Comparisons of the geomagnetic field component with reference data show that the original climatic overprint has been reduced by a factor of 2, outperforming a 10Be/9Be stack obtained from two sites with little glacial‐interglacial variability. The proposed method for removing climatic overprints can be applied to multiple sites more efficiently than conventional stacking. Key Points: A new technique for removing climatic overprints from geomagnetic records is presentedA worst‐case example based on a single cosmogenic 10Be record yields a reduction of environmental overprints by a factor of 2Cosmogenic 10Be is a better geomagnetic field proxy for the North Atlantic Ocean than 10Be normalized by 9Be [ABSTRACT FROM AUTHOR]

Pepper (Capsicum annuum L.) plants are extensively utilized in culinary and spice industries, rendering their cultivation pivotal in agricultural production. Enhancing their growth and yield is a critical research area for producers and horticulturists. Recent investigations have delved into the use of pulsed magnetic fields (PMFs) as a potential growth stimulant. Unlike static magnetic fields, PMFs are characterized by transient, high-intensity magnetic bursts, potentially eliciting varied responses in plants. To assess PMFs' impact on pepper plants, several experiments were setup comprising two solenoids, each wound around an 18-cm-diameter rigid plastic pipe but with differing coil turns, one with 40 and the other with 80 turns. These solenoids were utilized to generate PMFs at a frequency of 1 kHz with two intensities: 17 micro-Tesla (µT) and 34 µT. The pepper plants were situated within the PMF zone under controlled conditions, ensuring consistency in light, temperature, and moisture levels. The experimental design included three plant groups: a control group with no PMFs exposure except that of the Earth's magnetic field, and two groups subjected to 17 µT and 34 µT PMFs intensities with Earth's magnetic field, ranging between 25-65 µT. The treatment spanned 15 days, involving 6 hours of daily continuous exposure. Key growth indicators such as plant height, stem diameter, leaf area, and fresh and dry weights of both shoot and root systems were measured and analyzed. This analysis revealed significant increases in plant height, leaf area, and fresh and dry weights of the shoot, but not in root systems. Further research is warranted to deepen the understanding of PMFs' effects on pepper plants. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Magneto-Coriolis (MC) modes in Earth's fluid core involve oscillations sustained by the combined effect of the Lorentz and Coriolis forces. Here, we investigate the properties of MC modes that involve purely axisymmetric flow, which we term axiMC modes. We provide a basic description of the wave dynamics of these modes, and simple predictions for the expected scalings of their frequency |$\omega$|⁠ , decay rate |$\lambda$| and quality factor Q based on a uniform ambient magnetic field. In particular, Q scales with the Elsasser number |$\Lambda$|⁠ , which depends on the square of the r.m.s. strength of the azimuthally averaged meridional field. When |$\Lambda \gt 1$|⁠ , |$Q\gt 1$| and axiMC modes may be excited; when |$\Lambda \ll 1$|⁠ , |$Q\ll 1$| and axiMC modes revert to quasi-free magnetic decay modes. We present computations of axiMC modes in an inviscid, electrically conducting sphere for two idealized ambient magnetic field configurations, a uniform axial field and an axial poloidal field. We show that a flow gradient in the axial direction is a key property of axiMC modes. For the uniform axial field, |$\omega$|⁠ , |$\lambda$| and Q follow the scalings expected for a uniform field. For the axial poloidal field, the structure of the modes changes substantially when |$\Lambda \gtrsim 1$|⁠ , becoming more concentrated in regions of lower field strength. The combination of this structural change and advection of field lines by flow significantly increases |$\lambda$|⁠ , resulting in a Q that remains close to 1 even at high |$\Lambda$|⁠. For a magnetic field strength inside the Earth's core of a few mT, the gravest axiMC modes are expected to have periods in the range of one thousand to a few thousand years and a Q not substantially above 1. AxiMC modes may be connected to a part of the observed millennial changes in Earth's magnetic field, may exchange axial angular momentum with the mantle, and hence may also explain a part of the observed millennial changes in length of day. [ABSTRACT FROM AUTHOR]

This work follows on from studies carried out by Jiles and Atherton on magnetic hysteresis and on the magnetomechanical effect. The Jiles–Atherton equation, which models the rate of change of magnetization with respect to stress, was solved numerically in the forward and reverse directions for stress up to 90 MPa, suggesting that stressing carbon steel will cause a lasting change in the magnetization of the sample. This was confirmed experimentally by measuring the B-field in proximity to samples of C45 steel while undergoing tensile stress, with the pattern of magnetization suggesting that the magnetic domains reorient themselves in the geomagnetic field when stressing loosens their pinning. A further experiment on two samples confirms this, with the B-field around the samples showing strong changes according to their orientation in the geomagnetic field at the time of the stressing. This work has relevance to the non-destructive testing of steel structures such as pipelines, and the relevance of the experiments to this work is considered, as well as future prospects. [ABSTRACT FROM AUTHOR]

The polar cap arc at 1500 MLT (15MLT‐PCA) has been considered as an auroral signature of the cusp's duskside boundary and been speculated to be caused by lobe reconnection. However, no observational evidence has been provided to support this speculation. Here we report a 15MLT‐PCA event occurred on 29 November 2017 using multi‐instrument observations. During the DMSP observed the 15MLT‐PCA, Cluster, with its footprints at the root of the 15MLT‐PCA, identified two FTEs in the southern hemisphere's lobe region, accompanied by an increase in electron and ion energy from hundreds of eVs to several keVs. AMPERE observed an increase in upward field‐aligned currents associated with the 15MLT‐PCA. SuperDARN observed a single cell convection with an enhancement of sunward plasma flow near the root of 15MLT‐PCA. We suggest that these observations provide the in‐situ observational evidence that the 15MLT‐PCA is generated by a lobe reconnection at the cusp's duskside boundary. Plain Language Summary: Auroras primarily occur within an oval‐shaped region centered on Earth's magnetic poles. Under specific conditions, they can also occur within the polar cap, where auroral structures usually appear as arc‐like or spot‐like. Auroras exhibiting arc‐like structures in this region are collectively termed polar cap auroral arcs (PCA). One such common phenomenon is the 15 magnetic local time‐polar cap arc (15MLT‐PCA), typically observed near the 1500 MLT sector in the summer hemisphere, extending from the poleward boundary of the auroral oval to the pole. Additionally, its occurrence shows a strong dependence on the By component of the interplanetary magnetic field (IMF). It is widely accepted that the generation of north‐south asymmetric auroral structures in the polar cap results from reconnection between the IMF and Earth's magnetic field lines at high latitudes. Based on the observational characterization of 15MLT‐PCA, it is currently believed that this structure is associated with lobe reconnection. However, direct in situ observational evidence for this process is currently lacking. Therefore, in this study, we combined ionospheric and magnetospheric satellites to validate a possible magnetospheric process for 15MLT‐PCA. Key Points: The observations show that the occurrence of 15MLT‐PCA was accompanied by FTEs on the dusk flank of the southern hemisphere's magnetopauseThe 15MLT‐PCA is accompanied by an enhancement of upward FACs and an increase in sunward plasma flow near its rootWe provided evidence that the 15MLT‐PCA results from lobe reconnection occurring at duskside boundary of the cusp [ABSTRACT FROM AUTHOR]

Eight months of vector magnetic field measurements from the Macau Scientific Satellite‐1 (MSS‐1), supplemented by higher latitude field intensity measurements from the Swarm satellites, are used to derive an MSS‐1 Initial Field Model (MIFM). Robust root‐mean‐square misfits between MIFM and the three components of the MSS‐1 vector field data are found to be below 3.3 nT. MIFM agrees well with the CHAOS‐7 field model and we find even better agreement with an identically parameterized model derived only from Swarm data. MSS‐1 and Swarm vector data can moreover be fit simultaneously with only a small increase in misfit (by less than 0.2 nT). We show that both lithospheric anomalies and core surface field changes can be studied using MSS‐1 data. With its fast coverage of local times MSS‐1 is a valuable addition to the global geomagnetic observing system. Plain Language Summary: Earth's magnetic field is an essential part of our planetary environment. The global state of the field and its time variations are today carefully monitored from space by satellites. However rather few satellites provide measurements with the accuracy needed for detailed scientific studies and for the construction of geomagnetic reference models used for navigation. We show that vector magnetic field measurements from the Macau Scientific Satellite 1 (MSS‐1), launched in May 2023, are suitable for building high quality reference models of Earth's magnetic field. We show that time changes of field at the core‐mantle boundary and field anomalies related to lithospheric magnetization can be mapped using an initial 8 months of MSS‐1 data. Thanks to its low inclination orbit, MSS‐1 covers all local times, for latitudes up to ± $\pm $41°, within 2 months. This complements the coverage of existing polar‐orbiting satellites and provides new opportunities to study rapid geomagnetic field changes. Key Points: Macau Scientific Satellite‐1 provides the first vector magnetic field measurements with absolute accuracy from a low inclination orbitGeomagnetic field models constructed using vector data only from MSS‐1 are suitable for scientific studies of core and lithospheric fieldsBy covering all local times within 2 months, MSS‐1 provides a new class of observational constraints on rapid geomagnetic field variations [ABSTRACT FROM AUTHOR]

Both ground based magnetometers and ionospheric radars at Earth have frequently detected Ultra Low Frequency (ULF) fluctuations at discrete frequencies extending below one mHz‐range. Many dayside solar wind drivers have been convincingly demonstrated as driver mechanisms. In this paper we investigate and propose an additional, nightside generation mechanism of a low frequency magnetic field fluctuation. We propose that the Moon may excite a magnetic field perturbation of the order of 1 nT at discrete frequencies when it travels through the Earth's magnetotail ≈ ${\approx} $4–5 days every month. Our theoretical prediction is supported by a case study of ARTEMIS magnetic field measurements at the lunar orbit in the Earth's magnetotail. ARTEMIS detects statistically significant peaks in magnetic field fluctuation power at frequencies of 0.37–0.47 mHz that are not present in the solar wind. Plain Language Summary: Throughout history, the Moon has both captivated the human mind as well as had important practical consequences on the lives of people in coastal areas. Humans have attributed the Full Moon to all types of things, many of which do not stand up to scientific scrutiny. Recent spacecraft measurements have shown that the Moon has significant magnetic anomalies that are strong enough for producing a magnetic cavity in the solar wind plasma. The Moon also has a wake structure with a strong electrostatic potential which may act as a perturbation for the magnetic field lines. Here, by using ARTEMIS spacecraft observations in the magnetotail, we found surprisingly that the Moon may weakly perturb the Earth's magnetosphere when it travels through the magnetotail in about 4–5 days around the time of the Full Moon. This effect may have been stronger in the past, when Moon was closer to the Earth and its magnetic field was stronger. Key Points: A hypothesis for the Earth's magnetic field perturbation caused by the Moon in the magnetotail is proposedMagnetometer onboard ARTEMIS spacecraft detects the fundamental frequency corresponding to this theoretical predictionThese initial findings suggest the need for followup space and ground‐based statistical studies of the Moon‐Earth field line resonator [ABSTRACT FROM AUTHOR]

Mesoscales, which couple small to large scales, and vice‐versa, are critical to the magnetosphere‐ionosphere coupling. Optical and radar measurements indicate that dynamical mesoscale features are present in the ionosphere, however quantifying their contribution to the overall dynamics remains a challenge. We use a new ionospheric data assimilation technique, Lompe (Local mapping of the polar ionospheric electrodynamics), to specify ionospheric electrodynamics using a wide variety of input data and a priori assumptions about the physical nature of the ionospheric electric field. We isolate the terms of the ionospheric Ohm's law and find that mesoscale structures in the FACs are driven by Hall gradients, while the larger scale patterns are associated with the divergence of the electric field. We calculate the relative contribution of mesoscales to the overall FAC patterns during a magnetospheric substorm, and find that in the nightside, mesoscale FACs contribute up to 60% of the total. Plain Language Summary: Calculating the amount of energy input into Earth's ionosphere, the upper layer of the atmosphere, is extremely important as it is the endpoint for the Sun's interaction with the Earth's space environment. The ionosphere is coupled to the magnetosphere, the protective cavity carved by Earth's magnetic field as the solar wind flows around, through electrical currents aligned with the Earth's magnetic field called field aligned currents, or Birkeland currents. These currents occur at various spatial scales, from small to regional to semi‐global. Studying the time varying and spatial structure of these field‐aligned currents is important for quantitative understanding of the ionosphere‐magnetosphere system, with implications for space weather impacts via changes in neutral winds and density, local electron density enhancements, and so on. In this study, we quantify the amount of ionospheric regional scale (∼10−1000 ${\sim} 10-1000$ km) structures in the field aligned currents, and show that they are related to structures in the ionospheric conductances of the same scales sizes. Key Points: The Lompe data assimilation framework accurately captures both large‐scale and mesoscale FACsMesoscale FACs are 30% of the total FACs, and 50–60% of the nightside FACs during the magnetospheric substorm studied here [ABSTRACT FROM AUTHOR]

The movement history of boulders is crucial for the reconstruction of paleo‐tsunamis. We report findings from viscous remanent magnetization studies of the boulders on Tongatapu Island, aiming to reconstruct their reworkings. Two boulders exhibited viscous remanence, whereas two larger boulders lacked viscous components but exhibited stable remanence. Both the viscous and stable components deviated from the geomagnetic field direction. These observations indicate that: (a) the boulders with a viscous component were reworked before the latest event, which could have reworked all boulders, and (b) the magnitude of the latest event was larger than that of an earlier event. The reworked timing indicated that the event occurred between 3,000 years ago and the fifteenth century. The difference in the wave height required to move boulders on the eastern and western coasts suggests that the source of the earlier tsunami was likely an eruption due to volcanoes along the Tonga Ridge. Plain Language Summary: This study explores prehistoric tsunamis on Tongatapu Island by examining large rocks transported during the past tsunamis. Upon analyzing the magnetic records of the rocks, we discovered evidence of multiple rock movements, shedding light on the recurrence and magnitude of past events. Magnetic measurements and previously dated latest movement ages revealed that a tsunami occurred between 3,000 years ago and the fifteenth century. Considering the mobility and immobility of the large rocks and their sizes, the data suggest a smaller paleo‐tsunami magnitude than that of the fifteenth‐century event that transported all the rocks; this expands our understanding of natural hazard history and has implications for assessing tsunami risks in the region. The approach adopted here provides a valuable model for investigating historical natural disasters and their impact on coastal areas, offering insights to enhance global tsunami hazard assessment strategies. Key Points: Viscous remanent magnetization of large boulders indicates multiple reworkings, enhancing our understanding of past tsunamis in TongatapuCombined magnetic records and published radiocarbon ages suggest tsunamis occurred between 3,000 years ago and the fifteenth centuryRemanence and wave height estimates show that the older tsunami was smaller than the fifteenth‐century event, with a possible volcanic source [ABSTRACT FROM AUTHOR]

Magnetotactic bacteria (MTB) combine passive alignment with the Earth magnetic field with a chemotactic response (magneto-chemotaxis) to reach their optimal living depth in chemically stratified environments. Current magneto-aerotaxis models fail to explain the occurrence of MTB far below the oxic-anoxic interface and the coexistence of MTB cells with opposite magnetotactic polarity at depths that are unrelated with the redox gradient. Here we propose a modified model of polar magnetotaxis which explains these observations, as well as the distinct concentration profiles and magnetotactic advantages of two types of MTB inhabiting a freshwater sediment: a group of unidentified cocci (MC), and a giant rod-shaped bacterium (MB) apparently identical to M. bavaricum (MB). This model assumed that magnetotactic polarity is set by a threshold mechanism in counter gradients of oxygen and a second group of repellents, with, in case of MB, includes H+ ions. MTB possessing this type of polar magnetotaxis can shuttle between two limit depths across the redox gradient (redox taxis), as previously postulated for M. bavaricum and other members of the Nitrospirota group. The magnetotaxis of MB and MC is predominantly dipolar whenever the presence of a magnetic field ensures a magnetotactic advantage. In addition, MB can overcome unfavorable magnetic field configurations through a temporal sensing mechanism. The availability of threshold and temporal sensing mechanisms of different substances can generate a rich variety of responses by different types of MTB, enabling them to exploit multiple ecological niches. [ABSTRACT FROM AUTHOR]

The Earth's outer core dynamics involve convective fluid motion generating an observable geomagnetic field. The velocity and magnetic fields exhibit characteristic spatiotemporal features possessing geophysical significance for which extensive datasets are available from direct observations and computational simulations. This study demonstrates the robustness of proper orthogonal decomposition (POD), a data-driven technique, in detecting prominent and relevant features in these datasets. Improvising on previous practices, the POD efficiently detects infinitesimal instabilities at the onset of convection, providing an accurate and objective methodology to determine the convective threshold, even for heterogeneous buoyancy forcing. Time evolution of paired, phase-shifted modes efficiently reconstructs the azimuthally drifting of traveling wave instabilities. Simultaneously reduced order modeling of velocity components clearly distinguish the equatorial and polar coherent flow structures. Supercritical convection-driven magnetic field data over long periods, generated using numerical simulations, produce dominant modes that are more accurately representative of time-averaged patterns than geocentric axial dipole patterns. Moreover, the quantitative significance of the dominant modes determines the extent of dimensional reduction complementing established diagnostics for dipolarity. Finally, analysis of observational geomagnetic field data reveals long-lived dominant patterns influenced by thermal core–mantle interaction consistent with numerical models employing tomographic heat flux boundary conditions in present as well as previous studies. [ABSTRACT FROM AUTHOR]

Data on the absolute value of the geomagnetic field intensity at the beginning of the Cretaceous Normal Superchron (C34n) was obtained from basalts of Hooker Island of the Franz Josef Land archipelago (FJL). These basalts are considered as one of the manifestations of the High Arctic Large Igneous Province. The record of the ancient geomagnetic field in the studied Early Cretaceous basalts was preserved well due to the presence of pseudo-single domain grains of primary magmatic titanomagnetite. The paleointensity, obtained by the Thellier–Coe method, satisfies the generally accepted reliability criteria, taking into consideration other necessary evidence. This information indicates that 125 Ma, during the formation of the FJL traps, the intensity of the geomagnetic field was four times lower than today. Our estimates show that the mean value of the virtual dipole moment was 1.7 × 1022 Am2. These results support the views about the low paleointensity at the Barremian–Aptian boundary and indicate a correlation between the intensity of the geomagnetic field, the frequency of reversals, and the formation of mantle plumes. [ABSTRACT FROM AUTHOR]

A basaltic lava flow erupted from the Tajogaite volcano on 4 December 2021, in La Palma (Canary Islands, Spain) was sampled to find out to what extent reliable and correct information on both intensity and direction of the Earth's magnetic field can be obtained from the palaeomagnetic signal recorded in a lava flow which erupted under known conditions. Samples were taken every few centimetres across a flow up to a total of 27 oriented cores. Palaeomagnetic experiments showed a strong viscous overprint in many samples. Nevertheless, the mean palaeomagnetic direction obtained agrees well with the actual value from IGRF-13. Rock magnetic experiments were performed to obtain additional information about the quality and reliability of the results and the reasons for unsuccessful determinations. Analysis of mostly irreversible thermomagnetic curves showed that the carriers of remanence were magnetite and titanomagnetite of low and/or intermediate Curie-temperature. Hysteresis parameter ratios showed a pronounced variability across the flow. Analyses of frequency dependent susceptibility, IRM acquisition coercivity spectra and FORCs showed a noticeably presence of very low coercivity grains (multidomain and superparamagnetic-single domain boundary). Multimethod palaeointensity experiments were performed with the Thellier-Coe, multispecimen and Tsunakawa-Shaw methods. Only three of 25 cores from the flow yielded successful Thellier-Coe determinations, in agreement with the expected field value of 38.7 μT (IGRF-13). However, palaeointensities of 60 per cent of the specimens agree with the expected value performing an informal analysis without considering criteria thresholds. Four of six Tsunakawa-Shaw determinations performed on samples from the flow yielded correct results, but three multispecimen determinations providing apparently successful determinations largely underestimate the expected field intensity. Combination of three Thellier-Coe and four Tsunakawa-Shaw successful determinations yields a multimethod palaeointensity result B = (36.9 ± 2.0) μT in good agreement with the expected field intensity. [ABSTRACT FROM AUTHOR]

The article "Unraveling the Mystery of Lightning Superbolts" explores the phenomenon of superbolts, which are lightning strikes at least 1,000 times more powerful than ordinary lightning. These superbolts have been detected over oceans and are concentrated in specific regions, such as the North Atlantic and the Andes. Researchers have found correlations between superbolts and factors like the Earth's magnetic field, cosmic rays, and cloud formation. Despite their rarity, superbolts are a fascinating natural occurrence that scientists continue to study. [Extracted from the article]

Precambrian paleomagnetic studies are critical for testing paleogeographic reconstructions in deep time but rely on the fidelity of the assumption of the geocentric axial dipole (GAD) hypothesis. With high‐reliability data from mafic dykes and volcanic rocks, the scatter of individual virtual geomagnetic poles (VGPs) can be used to test simple GAD models. In order to conduct such a test, the VGPs must be adequate in number and in spatial coverage of the sampling sites. In this study, we targeted the 2.1 Ga Indin dyke swarm of the Slave craton. Building on previous sampling of the Indin dyke swarm in the western and central parts of southern Slave craton, we report results from 9 additional sites in the central and eastern parts of the craton, sites that significantly expand the width of the dyke swarm across the entire craton. The VGPs obtained from 7 of 9 newly identified Indin dykes are broadly similar to previously reported directions, expanding the total of VGPs for individual Indin dykes to n = 28, which is sufficient for a test of the GAD‐based statistical models using VGP scatter. The high VGP scatter of the Indin swarm can be attributed to the relatively high paleolatitude of 56° ± 6° for the Slave craton at the time of dyke emplacement. The Indin data have VGP scatter that is consistent with field models associated with the GAD hypothesis for the indicated paleolatitude, thus confirming the fidelity of the GAD field at ca. 2.1 Ga. Plain Language Summary: A fundamental assumption in paleomagnetism is the geocentric axial dipole (GAD) hypothesis. One feature of GAD that can be used to test it is that paleosecular variation (PSV) under a GAD field varies systematically with latitude, with its scatter being greater at relatively high latitudes than at low latitudes. Lavas and dykes for the past five million years and for various points in Earth's history generally support GAD, but there are some large gaps between these tests. Short‐term departures from GAD and/or intervals of weak fields have been suggested for certain time periods, highlighting the importance of regular tests of the GAD field throughout geological time. We study the ca. 2.1‐billion‐year‐old Indin dykes that fills one of these critical gaps. The Indin dyke swarm intruded across a large swath of the southern Slave craton, allowing us to extensively sample PSV. Our study finds a large VGP scatter for the Indin dykes, but as is to be expected given the relatively high paleolatitude. Thus, the scatter of Indin VGPs aligns with the GAD field model, confirming the reliability of the GAD field at ca. 2.1 Ga. Future studies of paleogeographic reconstruction during this period can confidently utilize paleomagnetism as a reliable quantitative constraint. Key Points: The ca. 2.1 Ga Indin dyke swarm has now been extensively sampled across much of the southern Slave cratonThe age and relatively high paleolatitude of the Indin dyke swarm provides an important constraint on the ancient magnetic fieldThe scatter of the paleomagnetic directions of the Indin dykes statistically supports a typical geomagnetic dipole field at 2.1 Ga [ABSTRACT FROM AUTHOR]

Seafloor fabric indicators are the main features used for dating global-scale plate reorganizations. However, the lack of oceanic crusts older than 200 Ma limits their application only to the Mesozoic and Cenozoic eras. Furthermore, in cases such as the mid-Cretaceous time when reversals in Earth's magnetic field did not occur, the plate reorganization ages obtained from seafloor fabric indicators are imprecise. I propose the record of continental deformation as an alternative approach for dating these events. A compilation of cooling/deformation, migmatization, and unconformity ages recorded around the globe collectively indicates that continental deformation associated with the mid-Cretaceous plate reorganization culminated at 107 Ma. This age strongly correlates with ages obtained from other data such as palaeomagnetic poles. Considering that the deformational features similar to which are compiled in this study appear to be temporally correlated with other reorganization events, the record of globally distributed continental deformation might be used for other reorganization events whose timing is poorly constrained. [ABSTRACT FROM AUTHOR]

Copyright of Progress in Earthquake Sciences is the property of China Earthquake Administration, Institute of Geophysics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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One of the fundamental problems of spacecraft dynamics related to ensuring its angular orientation in the basic coordinate system is considered. The problem of electrodynamic attitude control for a spacecraft in an elliptical near-Earth Keplerian orbit is studied. A mathematical model describing the attitude dynamics of the spacecraft under the action of the Lorentz torque, the magnetic interaction torque, and the gravitational torque is constructed. The multipole model of the Earth's magnetic field is used. The possibility of electrodynamic attitude control for the spacecraft's angular stabilization in the orbital frame is analyzed based on the Euler–Poisson differential equations. The problem of electrodynamic compensation of disturbing torque due to the orbit eccentricity is solved. The control strategy for spacecraft electrodynamic attitude stabilization is presented. Electromagnetic parameters that allow stabilizing the spacecraft's attitude position in the orbital frame are proposed. The disturbing gravity gradient torque is taken into account. The convergence of the control process is verified by computer modeling. Thus, the possibility and advisability of using the electrodynamic method for the spacecraft attitude control and its angular stabilization in the orbital coordinate system in an elliptical orbit is shown. [ABSTRACT FROM AUTHOR]

Large‐scale patterns of the steady‐state magnetosheath plasma flow and their dependence on the interplanetary magnetic field (IMF) have been reconstructed for the first time on the basis of large multi‐year multi‐mission pool of spacecraft observations, concurrent interplanetary data, and an empirical high‐resolution model. The flow model architecture builds upon a recently developed magnetosheath magnetic field representation by flexible expansions of its toroidal and poloidal components in a coordinate system, naturally conformed with the magnetopause and bow shock shapes. The model includes two physics‐based flow symmetry modes: the first one treats the magnetosphere as an axisymmetric unmagnetized obstacle, whereas the second mode takes into account the geodipole tilt, an important factor in the reconnection effects. The spacecraft data pool includes 1‐min average data by Themis (2007–2024), Cluster (2001–2022), and MMS‐1 (2015–2024) missions, as well as OMNI interplanetary data. The model drivers include the solar wind particle flux, IMF components, and the geodipole tilt angle. The model calculations faithfully reproduce the average plasma flow geometry and substantial effects have been found of the IMF orientation and magnitude, a principal factor that defines electromagnetic forces inside the magnetosheath. A strong dependence of the magnetosheath flow patterns on the Earth's dipole tilt indicates an important contribution of reconnection effects at the magnetopause to the solar wind particle transport around the dayside magnetosphere. Plain Language Summary: As a result of the solar wind interaction with the geomagnetic field, the Earth's magnetosphere becomes embedded within a huge "cocoon", a vast region between the bow shock and the magnetopause, where the incoming plasma stream gets compressed, heated, and diverted sideways around the magnetospheric boundary. An important factor that significantly affects the magnetosheath flow is the interplanetary magnetic field (IMF), transported to the Earth's orbit from the solar corona. The IMF undergoes compression and deformation inside the magnetosheath; the resulting electromagnetic forces substantially affect the plasma flow. Furthermore, the magnetic fields of solar and terrestrial origin can reconnect at the magnetopause, which results in additional modifications of the plasma flow pattern. During the last decades, huge amounts of satellite data were obtained in the near‐Earth space; using them in combination with a flexible mathematical model allowed us to quantitatively reconstruct the magnetosheath plasma flows and their dependence on the interplanetary factors and orientation of the Earth's magnetic dipole. The present paper describes first results of that study. Key Points: Large‐scale patterns of the magnetosheath plasma flow are reconstructed from multi‐year sets of in situ data and an advanced empirical modelSubstantial interplanetary magnetic field influence on the flow patterns is revealed, induced by magnetic field compression and tensions inside the magnetosheathPlasma flows significantly depend on the dipole tilt, indicating the important role of reconnection effects around the dayside magnetopause [ABSTRACT FROM AUTHOR]

Structural assessment of buried energy pipelines is often hindered by the abundance of external vibrations resulting in nebulous noises. Effective and secure nondestructive approaches need to be devised to efficiently reduce noise in multidimensional magnetic anomaly signals collected from a pipeline. This study focuses on the mechanism by which a measured source signal can be broken down into low- and high-frequency constituents known as intrinsic mode functions (IMFs). By doing so, a well-defined set of instantaneous frequencies is obtained utilizing improved complete ensemble empirical mode decomposition (ICEEMDAN) algorithms. These IMFs contain useful structural evidence across multiple scales that can be extracted for effective identification of the defect location. To accomplish this objective, first, the signal gradients are calculated using dual-density complex wavelet transform to diminish the influence of the geomagnetic field. The multiscale variance fusion (MVF) algorithm is then adopted to quantize the fluctuations occurring in each individual IMF. The output signals generated by computing the variances provide sufficient information about the location and severity of the pipeline defects. Numerical simulations for a buried pipeline model have been presented to validate the authenticity of the proposed technique. Indoor laboratory implantation on a pipeline test sample with prefabricated defects justifies the effectiveness of the ICEEMDAN-MVF model, to localize hidden structural flaws in energy pipelines without physical contact and even in more complex environments with multiple sources of magnetic interference. [ABSTRACT FROM AUTHOR]

Modern satellite positioning and navigation technologies are not applicable in specific areas such as the exploration of oil and gas deposits by means of directional drilling techniques. Here, we can rely solely on natural geophysical fields, such as the Earth's magnetic field. The precise underground navigation of borehole drilling instruments requires a seamless, near-real-time access to operational geomagnetic data. This paper describes the MAGNUS BD hardware-software system, deployed at the Geophysical Center of the Russian Academy of Sciences, that provides the efficient accumulation, storage, and processing of geomagnetic data. This system, based on the Big Data (BD) technology, is a modern successor of the MAGNUS processing software complex developed in 2016. MAGNUS BD represents one of the first cases of the BD technology's application to geomagnetic data. Its implementation provided a significant increase in the speed of information processing and allowed for the use of high-frequency geomagnetic satellite data and expanding the overall functionality of the system. During the MAGNUS BD system's deployment on a physically separate dedicated cluster, the existing classical database (DB) was migrated to the Arenadata database with full preservation of its functionality. This paper gives a brief analysis of the current problems of directional drilling geomagnetic support and outlines the possible solutions using the MAGNUS BD system. [ABSTRACT FROM AUTHOR]

Based on the magnetic field data recorded by the ZH‐1 electromagnetic satellite, we cerat a training set of 1,300 spectrograms containing the dispersion spectrum of lightning whistlers (LW). The Segment Anything Model (SAM) in the field of image segmentation is trained through the training set to obtain a fine‐tuned SAM model that can be used to detect and segment the dispersion spectrum of LW at pixel level. All track regions of LW are effectively separated from other non‐lightning whistlers regions in the spectrograms after being segmented by the model. The segmentation effect is excellent and detection accuracy is 96.89%, which is better than the previous segmentation model for LW based on ground station data. Then we apply the traditional image processing methods to extract the dispersion spectrum of LW one by one, and develop an algorithm to automatically extract the physical parameters of each LW. The root mean square error between the automatically extracted dispersion parameter and the manually extracted dispersion parameter is only 0.1654 s1/2. The model and algorithm studied in this paper are employed to analyze the dispersion of LW received by the ZH‐1 satellite over China. It is found that the whistlers dispersion received by satellites during summer in the northern hemisphere and summer in the southern hemisphere shows opposite trends with receiving latitude. Both trends can be explained by the relationship between the dispersion and the length of propagation paths of LW. Plain Language Summary: Lightning radiates out in the form of electromagnetic waves, and part of the very‐low‐frequency signal can leak into the ionosphere and propagate along the geomagnetic field lines to another hemisphere. Because this part of the signal has a whistle‐like sound, it is named lightning whistlers (LW). Due to the dispersion effect in the ionosphere, components with higher frequencies correspond to larger group velocity and propagate faster in the propagation process of LW. There is an L‐shaped dispersion pattern where the frequency gradually decreases with time in the spectrogram of whistlers. Image segmentation is an image recognition technique in the field of computer vision, aimed at assigning each pixel to a predefined category. Image segmentation technology can effectively separate all L‐shaped dispersion regions of whistlers from other non‐L‐shaped dispersion regions in the spectrograms, achieving automatic detection for whistles. The study in this paper is based on the electromagnetic data recorded by ZH‐1 satellite. We apply the Segment Anything Model in the field of image segmentation to detect and segment LW. The segmentation effect is excellent and detection accuracy is 96.89%. We then use the traditional image processing and develop an algorithm to automatically extract the physical parameters of each LW. Key Points: The image segmentation technology is firstly used to automatically detect and segment the lightning whistlers (LW) recorded by ZH‐1 satelliteAn algorithm based on image processing methods is proposed to automatically extract the physical parameters of detected LWThe model and algorithm studied in this paper are employed to analyze the dispersion of LW received by satellite over China [ABSTRACT FROM AUTHOR]

There is a long history of using VHF radar systems to detect ionospheric irregularities based on the theory of coherent scattering. According to previous work, there is a high occurrence of field-aligned irregularities (FAIs) in the ionospheric E-region over Kunming, China. In this paper, the VHF coherent scattering radar at Kunming is used to study the FAIs in the ionospheric E-region. Different arrangement of VHF radar antenna arrays, interferometry, and FAI echo parameter inversion methods are designed and tested. The measurement results show that the temporal and spatial characteristics of the irregularities can be obtained using these methods, as well as more refined spatial three-dimensional structure information. It is indicated that the new arrangement of the VHF radar antenna array is feasible to operate interferometry detection of E-region FAIs with the Kunming VHF radar. [ABSTRACT FROM AUTHOR]