Geomagnetic Storms Research Articles

Solar physics and space weather research at the Institute of Astronomy and NAO - BAS: Solar cycle trends of space weather drivers

Abstract This report summarizes the available space weather catalogs hosted at https://catalogs.astro.bas.bg/, supported by the Institute of Astronomy and National Astronomical Observatory – Bulgarian Academy of Sciences. Namely solar flares, solar energetic protons, electron associated radio bursts and geomagnetic storms are considered. All these comprehensive records of analysed events are provided with an open access with the aim to be supported in the future. The lists cover solar cycles 23 and 24 (1996–2019) and contain the relevant parameters and their associated solar and/or interplanetary origin. The focus of this report is the solar cycle trend of solar and geomagnetic phenomena, indicating reduced productivity of either type of events in the last solar cycle and offsets with respect to the sunspot numbers.

Inner Radiation Belt Simulations During the Successive Geomagnetic Storm Event of February 2022

AbstractStarting from 29 January 2022, a series of solar eruptions triggered a moderate geomagnetic storm on 3 February 2022, followed subsequently by another. Despite the typically minimal impact of unintense storms on space technology, 38 out of the 49 Starlink satellites underwent orbital decay, re‐entering Earth's atmosphere. These satellite losses were attributed to enhanced atmospheric drag conditions. This study employs numerical simulations, utilizing our test particle simulation code, to investigate the dynamics of the inner radiation belt during the two magnetic storms. Our analysis reveals an increase in proton density and fluxes during the transition from the recovery phase of the first storm to the initial phase of the second, primarily driven by intense solar wind dynamic pressure. Additionally, we assess Single Event Upset (SEU) rates, which exhibit a 50% increase in comparison to initial quiet conditions.

Using a Differential Magnetometer Technique to Measure Geomagnetically Induced Currents: An Augmented Approach

AbstractGeoelectric fields produced by time‐varying magnetic fields during geomagnetic storms can result in potentially damaging geomagnetically induced currents (GICs) in long conductors at the Earth's surface. GICs can pose a significant risk to the integrity of grounded electrical infrastructure, particularly high‐voltage transformers. In this study, an inferred GIC is calculated using an augmented differential magnetometer measurement (DMM) technique on a 500 kV transmission line in central Alberta and is validated using a proximal transformer neutral‐to‐ground (TNG) current measurement by AltaLink L.P. using a Hall probe at a transformer substation. This research outlines a custom‐built and innovative DMM design by which both DMM sensors deployed around a power line measure the background geomagnetic disturbance (GMD) field and the magnetic field generated locally by the GIC. We show how this modified approach provides two independent estimates for GIC derived using only ΔBy or ΔBz, the magnetic field components perpendicular to the line carrying GIC. Results for a geomagnetic storm on 12 Oct 2021 show contemporaneous peaks in the TNG current and the DMM‐inferred GIC. The two data sets have similar waveforms and are within the same order of magnitude. The background GMD is reconstructed using DMM and shows excellent correlation to the measured GMD at the permanent Canadian Array for Real‐time Investigations of Magnetic Activity magnetic station at Ministik Lake, approximately 48.5 km away. Based on the results presented here, we verify the added utility value of DMM for temporary deployments for assessing GIC risk in electrical power grids.

IMF Bx, By, and Bz dependence of energetic particle precipitation in the magnetosphere

The orientation of Interplanetary Magnetic Field (IMF B) components plays a major role in magnetospheric Energetic Particles Precipitation (EPP). This is because the IMF B components in the Geocentric Solar Magnetospheric (GSM) coordinate system control magnetic reconnection at the subsolar magnetopause. This study intends to unravel the dependence of the preceding conditions of the orientations of IMF B components that drove geomagnetic storms on the EPPs produced in the Van Allen radiation belt. We classified the geomagnetic storms based on their drivers and IMF Bz orientations prior to the storms’ onset. Energetic particle fluxes, IMF B, and solar wind data were used. The study showed that electrons are more reactive to solar wind speed than protons. Additionally, storms with southward IMF Bz orientation caused more EPP enhancement than with northward orientation. Our results also showed that protons are more influenced by magnetospheric compression than electrons at the northward orientation of IMF Bz. In fact, at this point, the proton’s motion violates adiabatic invariants. As particles interact with electric fields, a significant population of EPPs is produced by pitch angle diffusion. Generally, IMF Bx and IMF By are often anticorrelated. The preceding conditions of orientations of the IMF Bx indicated weaker dependence on auroral indices, and invariably on energetic particles precipitation than the IMF By.

Determination of Outer Radiation Belt MeV Electron Energization Rates and Delayed Response Times to Solar Wind Driving During Geomagnetic Storms

Determination of Outer Radiation Belt MeV Electron Energization Rates and Delayed Response Times to Solar Wind Driving During Geomagnetic Storms

Unveiling the Interplanetary Solar Radio Bursts of the 2024 Mother’s Day Solar Storm

We report on a comprehensive study of interplanetary type III radio bursts linked to X-class solar flares from NOAA active region 13664, which instigated the intense 2024 Mother’s Day solar storm, marked by a geomagnetic storm of −412 nT, the strongest in over two decades. Utilizing novel localization techniques with direction-finding data from STEREO-A, we identify an average eastward drift of 13.°42 ± 11.°63 in radio source locations relative to GOES observations. Our analysis reveals a significant correlation between solar flare intensity and longitude (Kendall’s tau = 0.535) and a strong correlation between radio flux at 1 MHz and GOES 1–8 Å soft X-ray flux (Kendall’s tau = 0.648). The timing analysis shows that peak soft X-ray fluxes typically follow electron beam liftoff by 3.24 ± 4.42 minutes. These insights into solar radio burst propagation and localization enhance our understanding of solar–terrestrial interactions and improve space weather forecasting capabilities.

Dynamics and solar wind control of the recovery of strong geomagnetic storms

Dynamics and solar wind control of the recovery of strong geomagnetic storms

Characteristics of radiation belt energetic protons and the movement of their core location in response to geomagnetic disturbances

The energetic protons trapped within the Earth's radiation belt play a crucial role in substantially impacting the behavior of the ring current, which in turn affects the dynamics of energetic particles. Here, we statistically analyze and discuss the global distributions and temporal evolutions of them at energies from 55 keV to 489 keV by using 7-year (2012–2019) observations by radiation belt storm probes ion composition experiment onboard Van Allen Probes. The observations show that low-energy protons (55–148 keV) are distributed at higher L shells (L > 4), which can deeply penetrate during intense storms. The high-energy protons (221–489 keV) are mainly located at L < 4.5 and are comparably stable. Moreover, the core location (i.e., Lc, the L shell with the peak flux) of them is typically energy-dependent and can be displaced due to geomagnetic storms. Detailed analysis reveals that the Lc for low-energy protons is primarily outside the plasmapause location (Lpp), which can rapidly radially move. However, the Lc for high-energy protons is essentially inside Lpp and is harder to move. The Lc for intermediate-energy protons exhibits fluctuations around Lpp, indicating a clear competition between source and loss processes. In addition, alternative mechanisms, such as wave–particle interactions, are primarily responsible for the gradual variation of them after storms. Our study provides the total configuration of the radiation belt energetic protons measured in the Van Allen Probe era, which would be useful for better understanding the variation of trapped particles in the inner magnetosphere.

Analysis of TEC variations and prediction of TEC by RNN during Indonesian earthquakes occurred from 2004 to 2024 and comparison with IRI-2020 model

The Ionosphere, a crucial region of Earth’s atmosphere extending from approximately 50 to 1000 km above the Earth’s surface, plays a pivotal role in global communication, navigation, and satellite-based technologies. Among its various parameters, Total Electron Content (TEC) stands out as a key metric, representing the integrated electron density along a specific path through the ionosphere. This research focuses on analyzing TEC variations during Indonesian earthquakes between 2004 and 2024 using a Recurrent Neural Network (RNN) model. The study investigates the ionospheric response to seismic activity, particularly in Indonesia, a region prone to earthquakes due to its location within the Pacific Ring of Fire and complex tectonic setting involving multiple lithospheric plates. The RNN model, designed to predict TEC variations during earthquakes, utilizes data on solar and geomagnetic activity, including the Kp index, solar wind, and geomagnetic storm activity, obtained from the OMNIWEB data centre, along with TEC data from the IONOLAB data servers for the BAKO station in Cibinong, Indonesia. The earthquakes considered for observation include significant events such as the 2004 Indian Ocean earthquake and tsunami, the 2012 Wharton Basin earthquake, and subsequent seismic events up to 2024. Statistical metrics such as Mean Bias Deviation (MBD), Relative Error (REL_E), Absolute Error (ABS_E), and Root Mean Square Error (RMSE) are used to evaluate the predictive capability of the RNN model and compare it with the International Reference Ionosphere (IRI) 2020 model, a widely accepted empirical model for describing ionospheric parameters. The comparison reveals the performance of the RNN model in capturing TEC variations during seismic events, providing valuable insights for earthquake monitoring and early warning systems.

New Anisotropic Cosmic-Ray Enhancement (ACRE) Event on 5 November 2023 Due to Complex Heliospheric Conditions

The variability of galactic cosmic rays near Earth is nearly isotropic and driven by large-scale heliospheric modulation but rarely can very local anisotropic events be observed in low-energy cosmic rays. These anisotropic cosmic-ray enhancement (ACRE) events are related to interplanetary transients. Until now, two such events have been known. Here, we report the discovery of the third ACRE event observed as an increase of up to 6.4% in count rates of high- and midlatitude neutron monitors between ca. 09 – 14 UT on 5 November 2023 followed by a moderate Forbush decrease and a strong geomagnetic storm. This is the first known observation of ACRE in the midrigidity range of up to 8 GV. The anisotropy axis of ACRE was in the nearly anti-Sun direction. Modeling of the geomagnetic conditions implies that the observed increase was not caused by a storm-induced weakening of the geomagnetic shielding. As suggested by a detailed analysis and qualitative modeling using the EUHFORIA model, the ACRE event was likely produced by the scattering of cosmic rays on an intense interplanetary flux rope propagating north of the Earth and causing a glancing encounter. The forthcoming Forbush decrease was caused by an interplanetary coronal mass ejection that hit Earth centrally. A comprehensive analysis of the ACRE and complex heliospheric conditions is presented. However, a full quantitative modeling of such a complex event is not possible even with the most advanced models and calls for further developments.

What Drove the GICs >10 A During the 17 March 2013 Event at Mäntsälä? A Novel Framework for Distinguishing the Magnetospheric Sources

AbstractWe combine wavelet analysis and data fusion to investigate geomagnetically induced currents (GICs) on the Mäntsälä pipeline and the associated horizontal geomagnetic field, BH, variations during the late main phase of the 17 March 2013 geomagnetic storm. The wavelet analysis decomposes the GIC and BH signals at increasing “scales” to show distinct multi‐minute spectral features around the GIC spikes. Four GIC spikes >10 A occurred while the pipeline was in the dusk sector—the first sine‐wave‐like spike at ∼16 UT was “compound.” It was followed by three “self‐similar” spikes 2 hr later. The contemporaneous multi‐resolution observations from ground‐(magnetometer, SuperMAG, SuperDARN), and space‐based (AMPERE, Two Wide‐Angle Imaging Neutral‐atom Spectrometers) platforms capture multi‐scale activity to reveal two magnetospheric modes causing the spikes. The GIC at ∼16 UT occurred in two parts with the negative spike associated with a transient sub‐auroral eastward electrojet that closed a developing partial ring current loop, whereas the positive spike developed with the arrival of the associated mesoscale flow‐channel in the auroral zone. The three spikes between 18 and 19 UT were due to bursty bulk flows (BBFs). We attribute all spikes to flow‐channel injections (substorms) of varying scales. We use previously published MHD simulations of the event to substantiate our conclusions, given the dearth of timely in‐situ satellite observations. Our results show that multi‐scale magnetosphere‐ionosphere activity that drives GICs can be understood using multi‐resolution analysis. This new framework of combining wavelet analysis with multi‐platform observations opens a research avenue for GIC investigations and other space weather impacts.

A Community Ionosphere‐Thermosphere Observing System Simulation Experiment (OSSE) Tool: Geospace Dynamics Constellation Example

AbstractObserving System Simulation Experiments (OSSEs) provide an effective way to evaluate the impact of assimilating data from a specific observing system on hindcasting, nowcasting, and forecasting of environmental systems. The NSF NCAR's Data Assimilation (DA) Research Testbed/Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (DART/TIEGCM) tool, to be hosted at the NASA Community Coordinated Modeling Center, serves as a valuable and accessible community resource for quantitatively evaluating the impact of observations from both current and future ionosphere‐thermosphere (IT) observing systems. This study demonstrates the utility of DART/TIEGCM as an IT OSSE tool, using synthetic observations simulated using a currently planned NASA Geospace Dynamics Constellation (GDC) observing system design. Five sets of OSSEs are carried out to compare the effects of assimilating various combinations of prospective GDC observations (e.g., neutral temperature, neutral wind, neutral composition, atomic oxygen ion density, and ion and electron temperature) during a major geomagnetic storm period of the St Patrick's Day Storm on 17 March 2013. The maximum error reduction in neutral temperature and atomic ion oxygen density is 24.6% and 43.3% compared to the control experiment. These OSSEs indicate the benefits of coupled IT DA approaches implemented in DART/TIEGCM to maximize the impact of multi‐parameter IT observations, such as those expected from the GDC mission. Although more work is required to draw any definitive conclusion on the GDC data impact, the study provides an illustrative example of how the DART/TIEGCM community tool can be used to evaluate observational impacts of planned or existing missions for geospace research and applications.

MAOOA‐Residual‐Attention‐BiConvLSTM: An Automated Deep Learning Framework for Global TEC Map Prediction

AbstractThe high‐precision prediction of total ionospheric electron content (TEC) is of great significance for improving the accuracy of global navigation satellite systems. There are two problems with the current prediction of TEC: (a) The existing TEC prediction models mainly based on stacked structure, which has insufficient predictive ability when the network has fewer layers, and loss of fine‐grained features when there are more layers, resulting in a decrease in predictive performance; (b) The existing research on ionospheric TEC prediction mainly focuses on building deep learning prediction models, while there is little research on optimizing the hyper‐parameters of TEC prediction models. Optimization can help find a better quasi‐optimal hyperparameter combination and improve the performance of the model. This paper proposed an automatic deep learning framework for global TEC map prediction, named MAOOA‐Residual‐Attitude‐BiConvLSTM. This framework includes a TEC prediction model, Residual‐Attention‐BiConvLSTM, which can simultaneously consider both coarse‐grained and fine‐grained spatiotemporal features. It also includes an optimization algorithm, MAOOA, for optimizing the hyper‐parameters of the model. We conducted comparative experiments between our framework and C1PG, ConvLSTM, ConvGRU, and ED‐ConvLSTM during high solar activity years, low solar activity years, and a magnetic storm event. The results indicate that in all cases, the framework proposed in this paper outperforms the comparative models.

Possible atmospheric-ionospheric precursors of the 2020 Hotan China earthquake from various satellites

The earthquake (EQ) precursors from satellites data portray an image of the energy propagation from the lithosphere to atmosphere and then to the ionosphere. Previous studies have often presented detailed discussion on different precursors at various altitudes. However, this study aimed to investigate the anomalies at various altitudes associated with the Hotan China EQ (hypocentral depth: 10 km, latitude 35.5°N, longitude 82.4°E). The goal was to identify pre-and post-seismic anomalies statistically in the conjunction with the wavelet transformation. We observed possible precursors in the atmosphere such as variations in aerosol optical depth, tropopause pressure, relative humidity, latent heat flux, and outgoing longwave radiation in a window of 5–10 days before the seismic event. Moreover, the total electron content had precursors during quiet geomagnetic storm conditions (−20 < Dst ≤ − 40 nT, Kp ≤ 3) beyond the bound within 5–10 days. These findings highlight the potential of using atmospheric and ionospheric parameters to detect seismic anomalies as EQ precursors for improved EQ early warning systems.

Impacts of Storm Electric Fields and Traveling Atmospheric Disturbances Over the Americas During 23–24 April 2023 Geomagnetic Storm: Experimental Analysis

Impacts of Storm Electric Fields and Traveling Atmospheric Disturbances Over the Americas During 23–24 April 2023 Geomagnetic Storm: Experimental Analysis

Geomagnetic Storms and Recording of Acoustic Signals

Geomagnetic Storms and Recording of Acoustic Signals

The effects of the May 2024 Mother’s Day superstorm over the Mediterranean sector: from data to public communication

On 8 May 2024, the solar active region AR13664 started releasing a series of intense solar flares. Those of class X released between 9 and 11 May 2024 gave rise to a chain of fast Coronal Mass Ejections (CMEs) that proved to be geoeffective. The Storm Sudden Commencement (SSC) of the resulting geomagnetic storm was registered on 10 May 2024 and it is, to date, the strongest event since November 2003. The May 2024 storm, named hereafter Mother’s Day storm, peaked with a Dst of –412 nT and stands out as a “standard candle” storm affecting modern era technologies prone to Space Weather threats. Moreover, the recovery phase exhibited almost no substorm signatures, making the Mother’s Day storm as a perfect storm example. Despite the plethora of notable near Earth environment modifications that are still under investigation, in this paper we concentrate on the Space Weather effects over the Mediterranean sector, with a focus on Italy. In fact, the Istituto Nazionale di Geofisica e Vulcanologia (INGV) manages a dense network of GNSS receivers (including scintillation receivers), ionosondes and magnetometers in the Mediterranean area, which facilitated for a detailed characterization of the modifications induced by the storm. Concerning the geomagnetic field, observatories located in Italy recorded a SSC with a rise time of only 3 minutes and a maximum variation of around 600 nT. The most notable ionospheric effect following the arrival of the disturbance was a significant decrease in plasma density on 11 May, resulting in a pronounced negative ionospheric storm registered on both the critical F2-layer frequency (foF2) and the Total Electron Content (TEC). Another negative effect was recorded on 13 May, while no signatures of composition changes and, specifically, to a decrease of the [O]/[N ] ratio. The IRI UP IONORING 2 data-assimilation procedure, recently developed to nowcast foF2 over Italy, proved to be quite reliable during this extreme event, being characterised just by an overestimation during the main phase of the storm, when the electron density and the height of the F region decreased and increased, respectively. Relevant outcomes of the work relate to the Rate Of TEC change Index (ROTI), which shows unusually high spatially distributed values on the nights of 10 and 11 May. The ROTI enhancements on 10 May might be linked to Stable Auroral Red (SAR) arcs and an equatorward displacement of the main ionospheric trough. Instead, the ROTI enhancements on 11 May might be triggered by a joint action of low-latitude plasma pushed poleward by the pre-reversal enhancement (PRE) in the post-sunset hours and wave-like perturbations propagating from the North. Furthermore, the storm generated immediate attention of the general public to Space Weather effects, including mid-latitude visible phenomena like SAR arcs. This paper outlines the report of the Space Weather Monitoring Group (SWMG) of the INGV Environment Department and its effort to disseminate information about this exceptional event.

What Drove the Carrington Event? An Analysis of Currents and Geospace Regions

AbstractThe 1859 Carrington event is the most intense geomagnetic storm in recorded history, and the literature provides numerous explanations for what drove the negative H perturbation on the Earth. There is debate on what dominated the event. Our analysis shows a combination of causes of similar orders of magnitude. Previous analyses generally rely upon the observed H perturbation at Colaba, India; historic newspaper reports; and empirical models. We expand the analysis using two Space Weather Modeling Framework simulations to examine what drove the event. We compute contributions from currents and geospace regions to the northward B field on Earth's surface, BN. We examine magnetospheric currents parallel and perpendicular to the local B field, ionospheric currents, and gap region field–aligned currents (FACs). We also evaluate contributions from the magnetosheath, near–Earth, and neutral sheet regions. A combination of currents and geospace regions significantly contribute to BN on the Earth's surface, changing as the storm evolves. At storm onset, magnetospheric currents and gap–region FACs dominate in the equatorial region. At auroral latitudes, gap–region FACs and ionospheric currents are the largest contributors. At storm peak, azimuthal magnetospheric currents and gap–region FACs dominate at equatorial latitudes. Gap–region FACs and ionospheric currents dominate in the auroral zone, down to mid‐latitudes. Both the magnetosheath and FACs contribute at storm peak, but are less significant than that from the near–Earth ring current. During recovery, the near–Earth ring current is the largest contributor at equatorial latitudes. Ionospheric currents and gap–region FACs dominate in the auroral zone.

Overview of the Space Weather Impact on the Navigation and Communication Systems

This article summarizes and analyzes the space weather impact on the Earth´s surface, aviation – especially navigation and communication aids, satellite functions ensuring communication, and GPS function. Forecasting the geomagnetic storms, solar radiation storms, radio blackouts, X-ray flux, and others is difficult due to the high variability of the space weather conditions and sun activity. It can change every hour and the exact space weather conditions and the impact on aviation for the future are hard to predict. This article shows some predictions and historical data regarding space weather activity, where the stated values were collected from the NOAA page. The article states the daily maximums or the maximums of predicted phenomena activity. Because of the complexity and the facts mentioned above, the historical data and predictions show the summary and most important phenomena of the day. The article consists of 3 main chapters: 1. Space Weather 2. Space Weather Impact on Technological Vulnerability 3. Space Weather Condition Overview in Data. The last chapter in this article is a conclusion that consists of and mentions some information about the used alternative methods when a GPS lapse occurs. Even though there are some alternate systems, but still using satellite-based navigation and communication aids is still the first option, and space weather events highly affect the systems and are a big hazard for aviation.

Variability of ionospheric ionization over Eurasia according to data from a high-latitude ionosonde chain during extreme magnetic storms in 2015

. We have examined longitudinal-temporal variations in ionospheric parameters over Eurasia by analyzing data from a chain of high-latitude ionosondes along a latitude circle ~70° N (geomagnetic latitudes 58°&lt;Glat&lt;65°) in the longitudinal sector 26–171° E during severe magnetic storms of solar cycle 24 in March and June 2015. To analyze the response of ionospheric ionization to geomagnetic disturbances, we have used ionosonde data on hourly average critical frequency foF2 of the ionospheric F2 layer. Strong differences were observed between common peculiarities of temporal variations in foF2 for the analyzed periods of magnetic storms, which are likely associated with the characteristic features of the seasonal and diurnal variations in the background high-latitude ionosphere of the given geographic region. During the main and early recovery phases of magnetic storms there were periods of blackouts of ionosonde radio signals. Differences in the character of the ionospheric response to geomagnetic disturbances have been noted. This is probably due to seasonal features of the probability of occurrence of the ionospheric storm positive or negative phase in different seasons of the year. The trends of increasing ionospheric ionization over the vast region of Eastern, Western Siberia and Europe after the end of the extreme magnetic storm in March 2015, according to measurements from the chain of high-latitude ionosondes, may be associated with the formation of an area of increased [O]/[N₂] ratio over this territory. Such an increase in ionospheric ionization exceeding the background level of foF2 values can be considered as a clear manifestation of the after-effect of magnetic storms.