Abstract We present a methodology that allows researchers to simulate in real time the spatiotemporal dynamics of ground electric field (GEF) given 3‐D conductivity model Earth based on continuously augmented data evolution inducing source. The formalism relies factorization source by spatial modes (SM) and series respective expansion coefficients exploits precomputed GEF kernels generated corresponding SM. To validate formalism, we invoke high‐resolution Fennoscandia consider realistic...

Abstract This study presents a time‐domain methodology for jointly modeling magnetic field variations resulting from ionospheric and magnetospheric currents, with the ultimate goal of improving imaging Earth's electrical conductivity at mantle depths. Three current systems–the equatorial electrojet (EEJ), polar (PEJ), mid‐latitude system (MLCS; called Sq in quiet times)–produce quasi‐periodic diurnal (DV). The longer‐period (LP) signals are primarily due to irregular fluctuations currents....

3-D interpretation of electromagnetic (EM) data different origin and scale becomes a common practice worldwide. However, EM numerical simulations (modeling)—a key part any analysis—with realistic levels complexity, accuracy spatial detail still remains challenging from the computational point view. We present novel, efficient solver based on volume integral equation (IE) method. The efficiency is achieved by using high-order polynomial (HOP) basis instead zero-order (piecewise constant) that...

Abstract During extreme space weather events the fluctuating geomagnetic field induces an electric in conducting Earth. This geoelectric turn generates currents ground‐based technological systems, affecting their operation. Thus, calculation of is a key step predicting, assessing, and, potentially, forecasting impact on critical infrastructure. We present approach and tool for first fully coupled regional three‐dimensional (3‐D) forward modeling electromagnetic from far geospace down to...

Abstract Ground‐based technological systems, such as power grids, can be affected by geomagnetically induced currents (GIC) during geomagnetic storms and magnetospheric substorms. This motivates the necessity to numerically simulate and, ultimately, forecast GIC. The prerequisite for GIC modeling in region of interest is simulation ground geoelectric field (GEF) same region. GEF its turn requires spatiotemporal specification source which generates GEF, well an adequate regional model Earth’s...

Abstract In this study, we present a tool to simultaneously invert multi‐source magnetic transfer functions (TFs), including tippers, solar global‐to‐local TFs originating from the signals due ionospheric source, and global Q ‐responses magnetospheric source. We jointly aforementioned constrain local conductivity structures beneath three islands in Atlantic (Tristan da Cunha), Indian (Cocos), Pacific (Oahu) Oceans. The recovered profiles appeared be consistent with presence of upper mantle...

Abstract There is significant interest in constraining mantle conductivity beneath oceans. One data source to probe oceanic magnetic fields measured at island observatories. From these local responses are estimated and then inverted terms of conductivity. However, may be strongly distorted by the ocean induction effect (OIE) originating from contrasts between land. Insufficiently accurate accounting for OIE lead wrong interpretation responses. generally modeled global simulations using...

Abstract The intensification of the fluctuating geomagnetic field during space weather events leads to generation a strong electric in conducting earth, which drives geomagnetically induced currents (GICs) grounded technological systems. GICs can severely affect functioning such infrastructure. ability realistically model ground (GEF) is important for understanding impact on We present results three‐dimensional (3‐D) modeling GEF eastern United States storm March 2015. external source...

The existence of subsurface oceans on the satellites giant planets and Trans-Neptunian objects has been predicted for some time. Liquid icy worlds, if present, exert a considerable influence dynamics ice–ocean system and, because astrobiological potential, represent an important objective future missions to outer solar system. Pluto–Charon is representative moon orbiting dwarf planet that believed have formed from remnants impact. evolution moons primarily controlled by mode efficiency heat...

Abstract In this study, we perform three‐dimensional (3‐D) ground electric field (GEF) modeling in Fennoscandia for three days of the Halloween geomagnetic storm (29–31 October 2003) using magnetic data from International Monitor Auroral Geomagnetic Effects (IMAGE) magnetometer network and a 3‐D conductivity model region. To explore influence inducing source on GEF simulations, consider different approaches to approximation. Within first two approaches, varies laterally, whereas third...

SUMMARY Most of the existing 3-D electromagnetic (EM) modelling solvers based on integral equation (IE) method exploit fast Fourier transform (FFT) to accelerate matrix–vector multiplications. This in turn requires a laterally uniform discretization domain. However, there is often need for multiscale and inversion, instance, properly account effects non-uniform distant structures and, at same time, accurately model from local anomalies. In such scenarios, usage grids leads excessive...

A conventional magnetotelluric (MT) survey layout implies measurements of horizontal electric and magnetic fields at every site with subsequent estimation interpretation impedance tensors $${Z}$$ or dependent responses, such as apparent resistivities phases. In this work, we assess advantages disadvantages complementing substituting MT inter-site transfer functions tensor, $${Q}$$ , magnetic, $${M}$$ electric, $${T}$$ tensors. Our analysis is based on a 3-D inversion synthetic responses...

Abstract Directional drilling in the oil fields relies particularly on “on‐fly” measurements of natural magnetic field (measurements while drilling; MWD); MWD are eventually used to construct well path. These superposition signals from internal, core and crustal, external, ionospheric magnetospheric sources noise elements borehole assembly. The internal mostly constant time accounted for through Earth's models. external origin give rise diurnal irregular spatio‐temporal variations observable...

SUMMARY In the past three decades, an immense amount of magnetic field data (with periods measurements from months to years) has been collected worldwide, either inland or at sea bottom. This makes it tempting estimate these magnetotelluric (MT) vertical transfer functions—tippers—and further probe with them 3-D distribution electrical conductivity on a continental even global scale. Such problem setup requires modelling tippers in spherical geometry. It is known that MT impedances...

Abstract We propose a novel approach to model the ground electric field (GEF) induced by laterally‐nonuniform ionospheric sources in real time. The exploits multi‐site transfer function concept, continuous magnetic measurements at multiple sites region of interest, and spatial modes describing source. compared modeled GEFs with those measured two locations Fennoscandia observed good agreement between GEF. Besides, we GEF‐based geomagnetically current (GIC) that Mäntsälä natural gas pipeline...

Abstract As part of a 5‐year project to assess the risk posed by geomagnetically induced currents (GIC) New Zealand electrical transmission network, long‐period magnetotelluric (MT) measurements have been made at 62 sites in southern South Island Zealand, region where there was an absence previous MT data. The data are largely 3‐dimensional character, but show distinct features that can be related known tectonic and geological structure. In this work we focus on how measured impedance...

Abstract We present a new model of the near‐Earth magnetospheric field produced by electric currents in inner magnetosphere and associated induced magnetic field. The is designed to track hourly variations these fields accounts for their local time asymmetries. It built applying spherical harmonic analysis vector measurements from ground observatory network at low mid‐latitudes. primary are separated with an approach domain that uses priori radially‐symmetric conductivity Earth. coefficients...

Abstract Vertical magnetic transfer functions (tippers) estimated at island observatories can constrain the one-dimensional (1-D) conductivity distribution of oceanic lithosphere and upper mantle. This is feasible due to bathymetry-dependent ocean induction effect (OIE), which originates from lateral contrasts between land leads non-zero tippers even for 1-D distributions below ocean. Proper analysis requires accurate three-dimensional (3-D) modeling OIE, so far was performed assuming...