Terrestrial Magnetic Field Research Articles

Martian Crustal Magnetic Field Effects on the Ionospheric Main Peak

Planetary magnetic fields can affect ionospheric plasma transport and coupling with the solar wind. In contrast to the terrestrial global magnetic field, there are only weaker and sporadic crustal magnetic fields on Mars. Many studies have indicated that Martian crustal fields can still modulate the topside ionosphere and its coupling with the solar wind. Nevertheless, it is unclear whether the crustal fields can affect the ionospheric main peak, which does not directly interact with the solar wind and is dominated by photochemical processes. In this study, the crustal field effect was identified from ionospheric measurements over unevenly distributed crustal fields. Both the intensity and configuration of the crustal fields were found to be capable of affecting the ionospheric main peak. The ionospheric peak electron density tends to decrease in the strong horizontal crustal field region. The results suggest that the crustal fields may affect the ionospheric main peak through modulating solar wind energetic particle precipitation; strong horizontal magnetic fields can partially prevent energetic particle precipitation and thus weaken impact ionization.

RAM‐SCB Runs on Request at CCMC

AbstractThe Ring current–Atmosphere interactions Model (RAM) with Self‐Consistent magnetic (B) field (SCB) combines a large‐scale kinetic model of ring current plasma with a three‐dimensional (3‐D) force‐balanced model of the terrestrial magnetic field. RAM‐SCB simulates the evolution of major ion species (H+, O+, and He+ by default) and electrons as a function of azimuth, radial distance, energy, and pitch angle. Simulation outputs include the Dst index, and pressure and differential flux of the modeled species, thus providing benefit as a science code and to inform surface charging hazard within the model domain. Version 2.2 of this open‐source simulation code has now—as of 8 August 2023—been made available for Runs‐On‐Request via the Community Coordinated Modeling Center.

Identifying and Visualizing Terrestrial Magnetospheric Topology using Geodesic Level Set Method

AbstractThis study introduces a novel numerical method for identifying and visualizing the terrestrial magnetic field topology in a large‐scale three‐dimensional global MHD (Magneto‐Hydro‐Dynamic) simulation. The (un)stable two‐dimensional manifolds are generated from critical points (CPs) located north and south of the magnetosphere using an improved geodesic level set method. A boundary value problem is solved numerically using a shooting method to forward a new geodesic level set from the previous set. These sets are generated starting from a small circle whose centre is a CP. The level sets are the sets of mesh points that form the magnetic manifold, which determines the magnetic field topology. In this study, a consistent method is proposed to determine the magnetospheric topology. Using this scheme, we successfully visualize a terrestrial magnetospheric field topology and identify its two neutral lines using the global MHD simulation. Our results present a terrestrial topology that agrees well with the recent magnetospheric physics and can help us understand various nonlinear magnetospheric dynamics and phenomena. Our visualization enables us to fill the gaps between current magnetospheric physics that can be observed via satellites and nonlinear dynamics, particularly, the bifurcation theory, in the future.

Influence of the Hypomagnetic Environment on the Metabolism and Psychophysiological Reactions of a Healthy Human

8 male volunteers aged 26 to 44 years were examined, who were in the “Arfa” hypomagnetic environment simulation facility for 4 hours at a normal magnetic field level (background session), and twice within 24 hours: one session during hypomagnetic environment simulation. environment with an attenuation coefficient of 500, and one − in the conditions of the terrestrial magnetic field (placebo). Venous blood was collected at the end of each session. The values of 48 biochemical parameters reflecting the state of organs and tissues, as well as the main links of metabolism, were determined in plasma and serum. Psychological testing of the testers was carried out using the questionnaires “Assessment of acute physical fatigue” by R. Kinsman and P. Weiser adapted by A.B. Leonova and “Assessment of acute mental fatigue” by A.B. Leonova and N.N. Savicheva. The level of physical condition of the participants of the experiment was assessed according to the method of D.N. Davidenko. As a result of the first biochemical screening examination and psychological testing of volunteers who were in a simulated space-level hypomagnetic environment, it was established that the effect is stressful, accompanied by the activation of glycolysis, lipolytic processes, affects the acid-base balance of the body, the state of the vascular endothelium, leads to to changes in the hepato-biliary system. At the same time, the index of physical fatigue among the volunteers increases, and the level of physical condition significantly decreases. Subjectively, pronounced changes in the biochemical parameters of stressful orientation are not felt.

High-Precision Magnetic Testbed Design and Simulation for LEO Small-Satellite Control Test

Small satellites with academic missions in low Earth orbit (LEO) employ magnetic attitude control systems primarily due to their ease of development and low cost. These systems utilize magnetorquers to generate a magnetic moment that interacts with Earth’s magnetic field, enabling controlled rotation of the satellite around its three axes. The successful execution of these satellite missions relies heavily on rigorous magnetic testing conducted on the Attitude Determination and Control (ADC) subsystem. Hence, the design of a magnetic field simulator that enables precise testing is of utmost importance. This paper presents a comprehensive study, analysis, and verification of the construction of a magnetic testbed capable of accurately reproducing terrestrial magnetic fields in low Earth orbits. The research was conducted in four stages. Firstly, Matlab/Simulink software was employed to predict the satellite’s orbit and the corresponding Earth’s magnetic field affecting it. Secondly, the three-axis magnetic testbed was simulated using Ansys Maxwell software to validate its technical characteristics. In the third stage, based on the previous data, the testbed was assembled and integrated into a university laboratory. Finally, calibration, testing, and verification of the testbed’s results were performed while reproducing Earth’s magnetic field from the satellite’s orbit. The final outcome was a flexible testbed design with the results exhibiting a precision exceeding 99.89%. This confirms that the magnetic testbed reliably generates results during small-satellite magnetic control tests.

The Series of Catastrophic Earthquakes of February 6, 2023, in Turkey and Variations in the Geophysical Fields

An analysis of variations in the microbaric background and the terrestrial magnetic and electric fields in the surface layer of the atmosphere accompanying strong earthquakes that occurred on February 6, 2023, in Turkey, is presented. The analysis involved the results of instrumental observations performed at the Moscow Center for Geophysical Monitoring and the Mikhnevo Observatory (Institute of Geospheric Dynamics, Russian Academy of Sciences), as well as the data obtained by a number of magnetic observatories of the INTERMAGNET network. It is shown that, in addition to the seismic effect, these earthquakes were accompanied by variations in the magnetic and electric fields, as well as by the generation of infrasonic waves recorded at a considerable distance from the sources.

Tides Ripple Across Earth’s Plasma “Doughnut”

Interactions between lunar gravity and the terrestrial magnetic field may cause a 90� offset from the Moon’s position in its orbit.

Influence of Cell Wall on Biomolecules Biosynthesis in Chlamydomonas reinhardtii Strains Exposed to Magnetic Fields

The application of magnetic fields (MF) has attracted the attention of researchers due to their efficiency to change cell metabolism. Chlamydomonas reinhardtii is a biotechnologically useful microalga with versatile metabolism that may be a valuable organism to study the effects of the MF in biology. Therefore, two C. reinhardtii strains, one with cell wall (2137) and other which lacks the cell wall (Wt-S1-cc4694), were evaluated that a new sensitivity factor in the analysis could be included. Comparative studies were undertaken with the two C. reinhardtii strains under the MF intensities of 0.005 mT (terrestrial MF - control), 11 and 20mT. Results indicated that the physical cell wall barrier protected cells against the MF applied during the assays. Only with the highest MF applied (20mT) a slight increase in lipid concentration in the cell wall strain was detected. The lowest growth of the strain that lacks cell wall (Wt-S1) indicated that these cells are under a negative effect. To cope with the two MF stresses conditions, Wt-S1 cells produced more pigments (chlorophylls and carotenoids) and lipids and enhanced the antioxidant defense system. The raise of these compounds under MF could potentially have a positive biotechnological impact on algal biomass.

Simulation of cosmic rays in the presence of a magnetic field

Cosmic rays damage microelectronics and have the potential to inflict great damage to life without the protection of the atmosphere and Earth's geomagnetic field (B field), which deflects the bulk of cosmic rays into space. When attempting to understand the observational measurements of cosmic rays, it is paramount to consider the effects magnetism will have on their trajectories. However, an analytical solution of the effects the B field has on cosmic ray trajectories is not possible because the cosmic ray flux is isotropic. We describe a new approach to numerically integrate, using Matrix Laboratory, the motion of cosmic particles deflected by a magnetic dipole field. We hypothesized that the numerical computation of cosmic ray trajectories through a magnetic dipole field, which approximates the Earth's B field, will validate the predictions of cosmic ray trajectories from known observational findings. The results of our study established the effects that the terrestrial magnetic field induces in the motions of these particles, as determined by the Lorentz Force. Overall, the trajectories of cosmic rays are determined by the particle’s energy and its interaction with the Earth’s B field. The high energy particles are curved, while the lower energy particles are either repelled or become trapped in the Earth's B field.

Transmission of foreshock waves through Earth’s bow shock

The Earth’s magnetosphere and its bow shock, which is formed by the interaction of the supersonic solar wind with the terrestrial magnetic field, constitute a rich natural laboratory enabling in situ investigations of universal plasma processes. Under suitable interplanetary magnetic field conditions, a foreshock with intense wave activity forms upstream of the bow shock. So-called 30 s waves, named after their typical period at Earth, are the dominant wave mode in the foreshock and play an important role in modulating the shape of the shock front and affect particle reflection at the shock. These waves are also observed inside the magnetosphere and down to the Earth’s surface, but how they are transmitted through the bow shock remains unknown. By combining state-of-the-art global numerical simulations and spacecraft observations, we demonstrate that the interaction of foreshock waves with the shock generates earthward-propagating, fast-mode waves, which reach the magnetosphere. These findings give crucial insight into the interaction of waves with collisionless shocks in general and their impact on the downstream medium.

Forecast of the Energetic Electron Environment of the Radiation Belts

AbstractDifferent modeling methodologies possess different strengths and weakness. For instance, data based models may provide superior accuracy but have a limited spatial coverage while physics based models may provide lower accuracy but provide greater spatial coverage. This study investigates the coupling of a data based model of the electron fluxes at geostationary orbit (GEO) with a numerical model of the radiation belt region to improve the resulting forecasts/pastcasts of electron fluxes over the whole radiation belt region. In particular, two coupling methods are investigated. The first assumes an average value for L* for GEO, namely = 6.2. The second uses a value of L* that varies with geomagnetic activity, quantified using the Kp index. As the terrestrial magnetic field responds to variations in geomagnetic activity, the value of L* will vary for a specific location. In this coupling method, the value of L* is calculated using the Kp driven Tsyganenko 89c magnetic field model for field line tracing. It is shown that this addition can result in changes in the initialization of the parameters at the Versatile Electron Radiation Belt model outer boundary. Model outputs are compared to Van Allen Probes MagEIS measurements of the electron fluxes in the inner magnetosphere for the March 2015 geomagnetic storm. It is found that the fixed coupling method produces a more realistic forecast.

Detecting Discontinuities From In Situ Space Measurements: Method and FPGA Implementation

AbstractThe analysis in real time of space data variability is essential for scientists and space mission controllers. Automated tools designed to extract key descriptors of variability are needed and solutions to adapt such algorithms for on‐board computers are rare. This paper describes the design of an automated system for detecting directional discontinuities of a physical quantity and its implementation in Field‐Programmable Gate Array (FPGA). The system is currently adapted for solar wind or terrestrial magnetosheath magnetic field directional discontinuities, that is, sharp changes of the magnetic field directionality. Our detection algorithm uses analysis windows of adjustable width and averaging procedures in order to reduce the effects of random fluctuations. A sliding‐window approach is designed for continuous monitoring and detection of magnetic directional discontinuities. A software implementation of the algorithm was tested using in‐situ magnetic field measurements, and emphasized improvements of performance when using analysis windows of adjustable width. The FPGA implementation of the detection algorithm is built on DILIGENT Nexys 4 DDR featuring a commercial Xilinx Artix‐7 device and is designed to be ported to space qualified infrastructure. The FPGA system was tested with synthetic and laboratory signals, and provides results in very good agreement with the software implementation. The FPGA system provides an efficient real‐time monitoring solution using minimal computational and energy resources, and reducing the main on‐board computer utilization.

Magnetically driven flow in a liquid-metal battery

This paper explores the fluid mechanics of liquid-metal batteries. It reaches the extraordinary conclusion that weak, stray magnetic fields, no larger than the terrestrial magnetic field, can drive turbulent motion within such a battery. This motion can have the beneficial effect of mixing, but if too violent, it will disrupt the operation of the battery. Stray magnetic fields significantly larger than the terrestrial field are generated when batteries are connected to form clusters within energy storage facilities.

Nonlinear evolution of internal gravity waves in the Earth’s ionosphere: Analytical and numerical approach

The nonlinear propagation of internal gravity waves in the weakly ionized, incompressible Earth’s ionosphere is studied using the fluid theory approach. Previous theory in the literature is advanced by the effects of the terrestrial inhomogeneous magnetic field embedded in weakly ionized ionospheric layers ranging in altitude from about 50 to 500 km. It is shown that the ionospheric conducting fluids can support the formation of solitary dipolar vortices (or modons). Both analytical and numerical solutions of the latter are obtained and analyzed. It is found that in absence of the Pedersen conductivity, different vortex structures with different space localization can be formed which can move with the supersonic velocity without any energy loss. However, its presence can cause the amplitude of the solitary vortices to decay with time and the vortex structure can completely disappear owing to the energy loss. Such energy loss can be delayed, i.e., the vortex structure can prevail for relatively a longer time if the nonlinear effects associated with either the stream function or the density variation become significantly higher than the dissipation due to the Pedersen conductivity. The main characteristic dynamic parameters are also defined which are in good correlation with the existing experimental data.

Time study of Earth’s magnetic field in Colombia: Fúquene Geomagnetic Observatory

In this article the behavior over time of the Earth’s magnetic field in the municipality of Fúquene, Colombia is determined. From the historical series of magnetic field measurements over the Earth’s surface provided by the Fúquene geomagnetic observatory, which contains the historical record of 60 years of hourly measurements of the terrestrial magnetic field components, a regression analysis of the terrestrial magnetic field components as a function of time was performed. Two methods were used to remove outliers that complemented each other, the Z_score method and the Hampel filter. In the analized period since 1955 to 2015, the intensity of the terrestrial magnetic field has decreased by 14%, with a projected variation of more than 25% for the year 2055. The magnetic field intensity change rate 0.08675 [μT/year] was calculated and compared with the information reported by NOAA (National Oceanica and Atmospheric Administration) finding an excellent agreement. Besides, the ocurrence of geomagnetic storms in the data was determined, from the gradients of the horizontal component of the magnetic field during the main solar events that occurred in the study period. According to the historical behavior of the terrestrial magnetic field components, in the future we expect that the decreasing of Earth’s magnetic Field continues, which would imply a higher threat to the effects of space weather in the country, such as the generation of GICs (Geomagnetically Induced Currents) in the Colombian electricity system.

Bayesian approach for auroral oval reconstruction from ground-based observations

Naked eye observations of aurorae might be used to obtain information on the large-scale magnetic field of the Earth at historic times. Their abundance may also help bridge gaps in observational time-series of proxies for solar activity such as the sunspot number or cosmogenic isotopes. With information derived from aurora observations like observing site, time of aurora sighting and position on the sky we can reconstruct the auroral oval. Since aurorae are correlated with geomagnetic indices like the Kp index, it is possible to obtain information about the terrestrial magnetic field in the form of the position of the magnetic poles as well as the magnetic disturbance level.Here we present a Bayesian approach to reconstruct the auroral oval from ground-based observations by using two different auroral oval models. With this method we can estimate the position of the magnetic poles in corrected geomagnetic coordinates as well as the Kp index. The method is first validated on synthetic observations before it is applied to four modern geomagnetic storms between 2003 and 2017 where ground-based reports and photographs were used to obtain the necessary information. Based on the four modern geomagnetic storms we have shown, that we are able to reconstruct the pole location with an average accuracy of ≈2° in latitude and ≈11° in longitude. The Kp index can be inferred with a precision of one class.The future goal is to employ the method to historical storms, where we expect somewhat higher uncertainties, since observations may be less accurate or not favorably distributed.

Active stabilization of terrestrial magnetic field with potassium atomic magnetometer.

This paper introduces a magnetically quiet environment where the magnetic-field noise is actively suppressed using an optically pumped potassium magnetometer. In a large dynamic range of Earth's magnetic fields, the magnetic-resonance signals of potassium are completely separated in frequency, and we experimentally demonstrate that one of them could be used to measure and compensate magnetic-field noise. The magnetic-field noise floor after stabilization is ∼100 fT/Hz under a bias field ranging from 20 to 100 μT. This method could be useful for fundamental-physics experiments and biomedical sciences where a large dynamic range of quiet magnetic fields is needed.

Search for dark-photon dark matter in the SuperMAG geomagnetic field dataset

In our recent companion paper [arXiv:2106.00022], we pointed out a novel signature of ultralight kinetically mixed dark-photon dark matter. This signature is a quasi-monochromatic, time-oscillating terrestrial magnetic field that takes a particular pattern over the surface of the Earth. In this work, we present a search for this signal in existing, unshielded magnetometer data recorded by geographically dispersed, geomagnetic stations. The dataset comes from the SuperMAG Collaboration and consists of measurements taken with one-minute cadence since 1970, with $\mathcal{O}(500)$ stations contributing in all. We aggregate the magnetic field measurements from all stations by projecting them onto a small set of global vector spherical harmonics (VSH) that capture the expected vectorial pattern of the signal at each station. Within each dark-photon coherence time, we use a data-driven technique to estimate the broadband background noise in the data, and search for excess narrowband power in this set of VSH components; we stack the searches in distinct coherence times incoherently. Following a Bayesian analysis approach that allows us to account for the stochastic nature of the dark-photon dark-matter field, we set exclusion bounds on the kinetic mixing parameter in the dark-photon dark-matter mass range $2\times10^{-18}\,\text{eV} \lesssim m_{A'} \lesssim 7\times10^{-17}\,\text{eV}$ (corresponding to frequencies $6\times 10^{-4}\,\text{Hz}\lesssim f_{A'} \lesssim 2\times 10^{-2}\,\text{Hz}$). These limits are complementary to various existing astrophysical constraints. Although our main analysis also identifies a number of candidate signals in the SuperMAG dataset, these appear to either fail or be in tension with various additional robustness checks we apply to those candidates. We report no robust and significant evidence for a dark-photon dark-matter signal in the SuperMAG dataset.

Magnetopause ripples going against the flow form azimuthally stationary surface waves

Surface waves process the turbulent disturbances which drive dynamics in many space, astrophysical and laboratory plasma systems, with the outer boundary of Earth’s magnetosphere, the magnetopause, providing an accessible environment to study them. Like waves on water, magnetopause surface waves are thought to travel in the direction of the driving solar wind, hence a paradigm in global magnetospheric dynamics of tailward propagation has been well-established. Here we show through multi-spacecraft observations, global simulations, and analytic theory that the lowest-frequency impulsively-excited magnetopause surface waves, with standing structure along the terrestrial magnetic field, propagate against the flow outside the boundary. Across a wide local time range (09–15h) the waves’ Poynting flux exactly balances the flow’s advective effect, leading to no net energy flux and thus stationary structure across the field also. Further down the equatorial flanks, however, advection dominates hence the waves travel downtail, seeding fluctuations at the resonant frequency which subsequently grow in amplitude via the Kelvin-Helmholtz instability and couple to magnetospheric body waves. This global response, contrary to the accepted paradigm, has implications on radiation belt, ionospheric, and auroral dynamics and potential applications to other dynamical systems.

Calculation, design and manufacture of heteropolar magnetic levitation and linear drive systems of maglev transport

Background: The methods of calculation and elements of the technology for creating heteropolar magnetic systems of levitation, lateral stabilization and a rotor-runner of a traction linear synchronous motor for the development of the transport technology "Russian Maglev" in order to achieve an increased levitation gap of 0.2 m, reduce the threshold speed of the exit vehicle in levitation mode up to 10 km/h.
 Aim: to develop methods for calculating and designing heteropolar poles from elementary permanent magnets, coils of the same type based on composite low-temperature superconductors and high-temperature tape superconductors of the second generation and a step-by-step technology for their production.
 Tasks:
 
 Creation of an on-board magnetic system of levitation and lateral stabilization, allowing to provide a levitation gap of 0.2 m, a threshold value of vehicle speed of 10 km/h when transition to levitation mode, to reduce stray magnetic fields to the level of the natural field of terrestrial magnetism of 50 T;
 Creation of a rotor-runner of a linear synchronous motor with an ironless stator with a power of 10 MW.
 
 Methods: outlines the main calculation methodologies: "analysis" and "synthesis". The "analysis" methodology is adopted in solving the "direct" calculation problem, when the configuration of the magnetic system is set and the magnetic field in the working area is calculated, and, if necessary, the stray magnetic fields. This methodology can be effectively applied if there is experience in creating magnetic systems. Otherwise, the "synthesis" methodology is applied, which is used in solving the "inverse" calculation problem, in which the picture of the distribution of the magnetic field in the working zone is set and the configuration of the magnetic system is found (synthesized).
 Results of the study performed:
 
 The parameters and characteristics of high-energy permanent magnets made of rare-earth metals, low-temperature and high-temperature superconducting winding materials have been analyzed, the choice of permanent magnets and superconducting winding material has been made;
 Calculations of the magnetic system of permanent magnets in the "Halbach assembly" and in the traditional assembly in a toothed ferromagnetic core have been carried out;
 Calculations of a track coil with a rectangular cross-section of the winding are performed;
 Methods for calculating and optimizing superconducting magnetic systems from a set of similar track modules have been developed;
 
 Conclusions: The results of the performed fundamental research will allow starting the calculation, design and construction of conveyor-main passenger and freight lines of maglev transport, as well as urban public transport.