A5019157235- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- Geophysics and Gravity Measurements
- Atmospheric Ozone and Climate
- Astro and Planetary Science
- Complex Systems and Time Series Analysis
- Magnetic Field Sensors Techniques
- GNSS positioning and interference
- Geophysical and Geoelectrical Methods
- Atomic and Subatomic Physics Research
- Plasma Diagnostics and Applications
- Geophysics and Sensor Technology
- Spacecraft Design and Technology
- Magnetic confinement fusion research
- Inertial Sensor and Navigation
- Seismic Waves and Analysis
- Metal and Thin Film Mechanics
- Scientific Research and Discoveries
- Electromagnetic Launch and Propulsion Technology
- Oceanographic and Atmospheric Processes
- Laser-induced spectroscopy and plasma
- Neural Networks and Applications
- Gas Sensing Nanomaterials and Sensors
Johns Hopkins University Applied Physics Laboratory
2016-2025
Johns Hopkins University
2010-2025
University of Bergen
2015-2024
Allentown Public Library
2021-2024
Br. Birkeland (Norway)
2014-2024
UiT The Arctic University of Norway
2022-2023
University of Michigan
2022
British Geological Survey
2022
Max Planck Institute for Solar System Research
2014
Goddard Space Flight Center
2000-2003
In this paper I outline the data processing technique which is used in SuperMAG initiative. a worldwide collaboration of organizations and national agencies that currently operate more than 300 ground based magnetometers. provides easy access to validated magnetic field perturbations same coordinate system, identical time resolution with common baseline removal approach. The purpose provide scientists, teachers, students general public measurements at surface Earth. Easy data, plots derived...
[1] We use magnetometer chains collaborating with SuperMAG to derive SME, a generalization of the auroral electrojet indices calculated from 100 or more sites instead 12 used in official indices, AE(12) = AU(12) − AL(12). investigate how these various relate nightside power by using both particle (DMSP) and image (Polar Ultraviolet Imager (UVI)) data. The best correlation is between SME total power, namely, r 0.86. Hence, nearly 3/4 minute-by-minute variance can be determined alone....
We present a statistical study of the temporal- and spatial-scale characteristics different field-aligned current (FAC) types derived with Swarm satellite formation. divide FACs into two classes: small-scale, up to some 10 km, which are carried predominantly by kinetic Alfvén waves, large-scale sizes more than 150 km. For determining temporal variability we consider measurements at same point, orbital crossovers near poles, but times. From correlation analysis obtain persistent period...
Examination of Geotail measurements in the near‐tail ( X > −30 R E ) has revealed presence small flux ropes plasma sheet. A total 73 rope events were identified magnetic field between November 1998 and April 1999. This corresponds to an estimated occurrence frequency ∼1 per 5 hours central sheet observing time. All embedded within high‐speed flows with 35 directed Earthward, 〈 V x 〉 = 431 km/s, 38 moving tailward, −451 km/s. We refer these two populations as “BBF‐type” “plasmoid‐type”...
With the motto “Knowledge is common wealth of humanity,” 2007–2008 Electronic Geophysical Year (eGY) advocated that scientists have responsibility to create and implement strategies utilize full potential digital capabilities in providing information for present future generations. Although eGY has officially ended, geomagnetic research community continues support goals through a global ground‐based magnetometer initiative. This initiative, called SuperMAG, helps easy access measurements...
[1] A generalization of the traditional 12-station auroral electrojet (AE) index to include more than 100 magnetometer stations, SME, is an excellent predictor global power (AP), even at high cadence (1 min). We use this index, and a database 53,000 substorms derived from it, covering 1980–2009, investigate time energy scales in magnetosphere, during otherwise. find, contrary common opinion, that do not have preferred recurrence rate but instead two distinct dynamic regimes, each following...
Using the extensive set of stations in SuperMAG collaboration, we introduce partial ring current indices, which provide new insights into development. The indices are labeled SMR‐ 00, 06, 12 and 18 for their center local time range. These incorporate data from 98 mid low latitude stations. behavior these during storms substorms, on both an individual superposed epoch basis, produces consistent patterns. initial positive spike before a storm, results solar wind pressure enhancements, is seen...
We present a new quantitative technique that determines the times and durations of substorm expansion recovery phases possible growth based on percentiles rate change auroral electrojet indices. By being able to prescribe different percentile values, we can determine onset duration for smaller or larger variations index indeed any zone ground-based magnetometer data. apply this SuperMAG AL (SML) compare our phase with previous lists onsets. find more than 50% events in occur within 20 min...
Abstract. We examine particularly intense substorms (SML ≤–2500 nT), hereafter called "supersubstorms" or SSS events, to identify their nature and magnetic storm dependences. It is found that these are typically isolated events only loosely related storms. can occur during super (Dst ≤–250 nT) (−100 nT ≥ Dst >–250) also nonstorm ≥–50 intervals. SSSs important because the strongest ionospheric currents will flow potentially causing power...
Abstract The physical magnetospheric cause for geomagnetically induced currents (GICs) are rapid time‐varying magnetic fields (dB/dt), which occur mainly during substorms and storms. When, where why exactly such dB/dt may is insufficiently understood. We investigated all storms since 1980 analyzed the negative positive spikes (>|500| nT/min) in north east component using a worldwide coverage (SuperMAG). Our analysis confirmed existence of two “hotspots” located pre‐midnight morning local...
Abstract We investigate sharp changes in magnetic field that can produce Geomagnetically Induced Currents (GICs) which damage pipelines and power grids. use one‐minute cadence SuperMAG observations to find the occurrence distribution of “spikes.” Recent studies have determined recurrence statistics for extreme events charted local time spikes; however, their relation solar activity conditions wind is poorly understood. study spike during cycles 23 24, roughly 1995 2020. three hotspots...
Abstract The occurrence of geomagnetically induced currents (GICs) poses serious threats to modern technological infrastructure. Large GICs result from sharp variations the geomagnetic field (d B /d t ) caused by changes large‐scale magnetospheric and ionospheric currents. Intense d perturbations are known occur often in high‐latitude regions as a storm time substorms. Magnetospheric compressions usually interplanetary shocks increase magnetopause current leading more evident midlatitude...
Abstract We study extremely intense substorms with SuperMAG AL (SML) peak intensities < −2500 nT (“supersubstorms”/SSSs) for the period from 1981 to 2012. The SSS events were often found be isolated SML peaks and not statistical fluctuations of indices. SSSs occur during all phases solar cycle highest occurrence (3.8 year −1 ) in descending phase. exhibited an annual variation equinoctial maximum altering between spring 22 fall 23. rate strength did show any strong relationship intensity...
Abstract The goal of the present study is to observationally test idea that substorm current wedge (SCW) an ensemble wedgelets, mesoscale systems correspond plasma sheet flow channels. According this hypothesis, SML index, SuperMAG equivalent AL represents a single particular wedgelet at given time, whereas midlatitude positive bays are sum remote effects all wedgelets but with more weighting on ones closer in longitude. However, both event‐based and statistical studies isolated substorms...
This paper presents a multi-parameter global statistical model of extreme horizontal geomagnetic field fluctuations (d B H /d t ), which are useful input to models assessing the risk geomagnetically induced currents in ground infrastructure. Generalised Pareto (GP) distributions were fitted 1-min measurements |d | from 125 magnetometers (with an average 28 years data per site) and return levels (RL) predicted for periods (RP) between 5 500 years. Analytical functions characterise profiles...
Abstract Learning from successful applications of methods originating in statistical mechanics, complex systems science, or information theory one scientific field (e.g., atmospheric physics climatology) can provide important insights conceptual ideas for other areas space sciences) even stimulate new research questions and approaches. For instance, quantification attribution dynamical complexity output time series nonlinear is a key challenge across disciplines. Especially the physics, an...
Abstract In this work, we present a statistical study of substorms covering five‐year period 2016–2020. Substorm phases were identified from time series the SuperMAG AL (SML) index using list 5,077 previously substorm onsets, SML peak value marking transition expansion to recovery phase, and as return activity less than −100 nT in index. Magnetic field observations THEMIS, RBSP, MMS missions used magnetotail characteristics during evolution. A superposed epoch analysis indicates that onset...
Abstract. We present the first ever comprehensive statistical study of spatiotemporal characteristics field-aligned currents in terrestrial magnetosphere-ionosphere system using multi point measurements. determine how FAC density, variability and scale size are coupled. The three ST 5 satellites were a pearls-on-a-string formation making measurements magnetic field with variable inter-spacecraft separations ranging from few seconds to about 10 min. More than 4700 sets satellite passes...
Abstract We present an empirical model of the equivalent current system in ionosphere during peak a classical bulge‐type auroral substorm. This is derived from measurements made by ~110 ground magnetometer stations 116 substorms. The data are temporally and spatially organized using global images obtained Polar Visible Imaging System Earth Camera. displays three key features: poleward shift westward electrojet connecting postmidnight premidnight components; polar cap swirl; significantly...
Recent results by the Van Allen Probes mission showed that occurrence of energetic ion injections inside geosynchronous orbit could be very frequent throughout main phase a geomagnetic storm. Understanding, therefore, formation and evolution particle is critical in order to quantify their effect inner magnetosphere. We present case study substorm event occurred during weak storm $\textit{ Dst }$ $\sim$ -40nT on 14 July 2013. Probe B, orbit, observed two proton within 10min, with different...
Abstract Abrupt variations of auroral electrojets can induce geomagnetically induced currents, and the ability to model forecast them is a pressing goal space weather research. We report an electrojet spike event that extreme in magnitude, explosive nature, global spatial extent occurred on 24 April 2023. The serves as fundamental test our understanding response geospace system solar wind dynamics. Our results illustrate new important characteristics are drastically different from existing...
Abstract During periods of increased geomagnetic activity, perturbations within the terrestrial magnetosphere are known to induce currents conducting materials, at surface Earth through rapid changes in local magnetic field over time ( dB / dt ). These as geomagnetically induced and have potentially detrimental effects on ground based infrastructure. In this study we undertake case studies five storms, analyzing a total 19 days 1‐s SuperMAG data order better understand (MLT) distribution,...