Sodari, now in the third year of his Ph.D. program in physics at UTA, received a three-year fellowship that provides an annual stipend of $50,000. This award enables him to embark on an ambitious project titled “Morphology of Equatorial Ionization Anomaly: GOLD Observations and GITM-SAMI3 Simulations,” which investigates a pivotal component of Earth’s upper atmosphere known as the Equatorial Ionization Anomaly (EIA). The EIA is a crucial phenomenon occurring in the ionosphere, marked by two distinct electron density peaks situated symmetrically around the magnetic equator, separated by a trough of significantly reduced plasma density.

The ionosphere itself is an electrically charged layer of the atmosphere that extends roughly from 50 to 400 miles above Earth’s surface and is vital for its interaction with radio waves and satellite communications. Variability within the EIA, affected by solar radiation and geomagnetic activity, has a profound impact on GPS accuracy, satellite signal integrity, and communication systems, particularly in regions near the equator where the anomaly is most prominent. Sodari’s research aims to delineate the complex spatial and temporal dynamics governing these ionospheric structures and their evolution during various geomagnetic conditions.

Central to this exploration is data from NASA’s Global-scale Observations of Limb and Disk (GOLD) mission. Launched in 2018, GOLD utilizes a unique imaging instrument aboard a geostationary communications satellite, permitting continuous global observations of the thermosphere and ionosphere. Sodari’s research leverages GOLD’s unprecedented measurements to capture real-time variations in the EIA, enabling comprehensive evaluation of its morphology across local time, longitude, and magnetic disturbances.

To complement observational data, Sodari integrates two sophisticated computational models: the Global Ionosphere Thermosphere Model (GITM) and SAMI3, the three-dimensional ionosphere-plasmasphere model. GITM simulates the coupled dynamics of the ionosphere and thermosphere by incorporating solar inputs, atmospheric chemistry, and electrodynamics. SAMI3, on the other hand, specializes in resolving the complex plasma behaviors within the ionosphere and plasmasphere system. By juxtaposing GOLD observations with these models, Sodari seeks to unravel the driving physical processes behind the post-sunset dynamics and morphological variations of the EIA crests.

This multidisciplinary approach, combining satellite-based remote sensing with state-of-the-art numerical modeling, allows for a nuanced understanding of how geomagnetic storms and solar activities modulate ionospheric densities and structures. Such knowledge is critical in refining space weather prediction capabilities, ultimately safeguarding vulnerable technologies reliant on precise satellite navigation and reliable communication channels.

Sodari embarked on his doctoral journey at UTA in August 2023, drawn by the institution’s robust space science research environment and mentorship from faculty leaders specializing in magnetosphere-ionosphere-thermosphere coupling. His advisor, Assistant Professor Zihan Wang, emphasized Sodari’s exceptional motivation and potential as a young scientist, noting that this recognition by NASA affirms the strength of UTA’s physics graduate program on a national level.

One particularly challenging aspect of studying the EIA lies in understanding its post-sunset behavior, a period when the anomaly’s density crests undergo significant morphological changes influenced by complex electrodynamic forces and neutral atmospheric winds. Changes during geomagnetically disturbed periods can lead to the weakening or intensification of the plasma crests, which in turn affects electron density profiles crucial for radio wave propagation through the ionosphere.

By studying these variations through both empirical and theoretical lenses, Sodari’s work addresses a critical gap in current space weather modeling. Disruption in the EIA can lead to degraded positional accuracy in GPS systems, which has wide-reaching implications for aviation, maritime navigation, military operations, and civilian applications. Furthermore, understanding the EIA’s underlying physics enhances predictive models that guide satellite operational protocols during solar storms.

NASA’s mission to better comprehend Earth’s upper atmosphere is essential not only for scientific inquiry but also for the societal and technological challenges posed by an increasingly space-reliant world. With space weather phenomena influencing everything from communication networks to power grids, research like Sodari’s on the fine-scale morphology of ionospheric anomalies plays a decisive role in mitigating these risks.

Looking forward, Sodari aims to contribute substantive insights into how solar-terrestrial interactions manifest at low latitudes, fostering improved forecasting methods. By elucidating the physical mechanisms that govern the EIA’s spatial structure and temporal evolution, his research stands to enhance models that predict space weather impacts with greater precision. Such advancements are invaluable for both protecting existing infrastructure and designing resilient systems for the future.

This fellowship and subsequent study mark an exciting phase in Sodari’s academic career and the broader exploration of Earth’s space environment. His work exemplifies a new generation of physicists harnessing sophisticated technology and computational power to decode the complexities of near-Earth space, bridging observational data with theoretical frameworks to address global challenges.

In sum, Tapendra Sodari’s selection for the FINESST fellowship highlights the vital role of emerging scientists in advancing space weather science. His research not only deepens understanding of ionospheric phenomena like the Equatorial Ionization Anomaly but also reinforces the critical connection between fundamental physics studies and practical technological outcomes essential for modern society.

Subject of Research: Morphology and dynamics of the Equatorial Ionization Anomaly using satellite observations and advanced ionosphere-thermosphere models.

Article Title: NASA Awards Future Investigators Fellowship to NASA Earth and Space Science Ph.D. Candidate at UTA for Upper Atmospheric Research

News Publication Date: (Not provided)

Web References: https://mediasvc.eurekalert.org/Api/v1/Multimedia/58f14a19-5b05-430d-b9f1-6c66dfcd2ce9/Rendition/low-res/Content/Public

Image Credits: University of Texas at Arlington (UT Arlington)

Keywords: Equatorial Ionization Anomaly, ionosphere, thermosphere, GPS accuracy, space weather, NASA GOLD mission, GITM model, SAMI3 model, plasma morphology, geomagnetic disturbances, upper atmosphere, space technology.

The research team capitalized on nearly 40 years of helioseismic observations gathered by the Birmingham Solar Oscillations Network (BiSON). Unlike traditional methods that track solar phenomena only on or above the surface, helioseismology probes the Sun’s interior by analyzing sound waves resonating within it. These acoustic oscillations, known as p-modes, fluctuate in frequency in response to the Sun’s magnetic environment. Through detailed analysis of these frequency variations over solar cycles 22 through 25, spanning from 1987 to 2025, the study illuminated subtle but significant changes in the Sun’s subsurface magnetic structure.

The pivotal finding indicates that the Sun’s magnetic activity—historically diffused across various layers of the solar interior—is becoming increasingly confined to a shallow stratum roughly within 1,000 kilometers beneath the surface. This “skin-deep” localization contrasts markedly with previous cycles where magnetic phenomena permeated more deeply into the Sun’s interior. Such confinement suggests a marked reorganization in how solar magnetic fields are generated, stored, and evolve, potentially marking a long-term shift in solar dynamics.

Professor Bill Chaplin, leading the study, articulated this phenomenon as the Sun’s “active biorhythm,” a complex cadence of magnetic rise and fall that shapes space weather. The helioseismic data reveals that the connection between internal solar oscillations and surface magnetic activity indicators has shifted since solar cycle 23, signaling an evolutionary change in the Sun’s internal processes. This disparity underscores the limits of surface observations alone in grappling with the full complexity of solar activity.

Delving into the methodology, the study segregated the solar oscillations into low-, mid-, and high-frequency bands. Each frequency band probes a different depth below the solar surface, allowing researchers to map structural and magnetic variations at discrete layers. By comparing these oscillatory signatures with traditional surface activity metrics, the team discerned that while the surface magnetic indicators might reflect a weakening in the latest cycle (cycle 25), helioseismic data, particularly from high-frequency oscillations, reveal a persistently strong magnetic intensity beneath the surface.

This nuanced discrepancy not only challenges current models of solar cycle strength assessment but also indicates a potential shift in the underlying physics of the solar dynamo—the internal mechanism powering magnetic field generation. Professor Sarbani Basu of Yale University, a co-author of the study, emphasized that the evolving relationship between internal oscillations and surface magnetism cannot be explained simply by weaker magnetic fields. Instead, it points towards complex structural reorganization in the Sun’s magnetic storage and transport mechanisms within its outer layers.

Understanding these internal dynamics is crucial, as the Sun’s magnetic cycle directly impacts space weather. Periods of high solar activity, or solar maxima, often unleash intense solar flares and energetic particle storms that can disrupt global positioning systems, satellite operations, and terrestrial electrical infrastructures. As the Sun’s magnetic phenomena become more confined near the surface, this could influence the timing, intensity, and characteristics of such space weather events in ways not fully anticipated today.

The long-term BiSON dataset was instrumental in making this discovery possible. Such an extended observational record spanning nearly four decades allowed the researchers to detect subtle, systematic trends that would have otherwise remained obscured by shorter-term variability. The current Cycle 25 appears to be a particularly telling case, exhibiting pronounced signatures of the newly observed confinement effect, thus offering a natural laboratory for further study.

Looking ahead, continuous monitoring of solar oscillations through the remainder of Cycle 25 and into the upcoming Cycle 26 stands as a pivotal undertaking. Confirming whether these structural changes signify a permanent transformation or a transient fluctuation will refine modeling efforts and enhance predictive capabilities for solar activity. Such predictions hold the promise of mitigating the impact of space weather on crucial technologies and infrastructure on Earth and in orbit.

Beyond their immediate relevance to heliophysics, these findings offer profound insights into stellar physics more broadly. The Sun serves as the primary astrophysical laboratory for understanding magnetic activity in stars, and discoveries of restructured magnetic layering may aid in interpreting similar processes observed in other stars. Asteroseismology—the study of stellar oscillations—is poised to benefit from this pioneering work by providing new frameworks for connecting internal stellar dynamics with surface phenomena.

As the scientific community digests these revelations, the message is clear: the Sun is not a static entity but a dynamic star whose internal processes evolve over decades. Our capacity to “listen” to the Sun’s acoustic symphony has reshaped our understanding, revealing a vibrant, changing interior landscape intimately linked to the magnetic forces sculpting space weather. This research highlights the importance of sustained, high-precision observations and sets the stage for the next generation of solar physics investigations.

In sum, the evolving confinement of solar magnetic activity near the surface challenges pre-existing paradigms and underscores the need for comprehensive, multi-layered approaches to unravel the complexity of our star’s behavior. With space weather increasingly entwined with our technological civilization’s fabric, deciphering the Sun’s internal transformations remains a compelling scientific frontier with tangible societal implications.

Subject of Research: Changes in solar interior structure and magnetic activity using helioseismology.

Article Title: Sub-surface structural changes associated with successive 11-yr solar activity cycles have been progressively more confined near the surface: new helioseismic results on Cycles 22–25 from BiSON

News Publication Date: 28-May-2026

References: Chaplin, W. J., et al. (2026). Sub-surface structural changes associated with successive 11-yr solar activity cycles have been progressively more confined near the surface: new helioseismic results on Cycles 22–25 from BiSON. Monthly Notices of the Royal Astronomical Society.

Image Credits: W. J. Chaplin

Keywords

Solar activity, solar cycles, helioseismology, stellar oscillations, solar interior, magnetic fields, space weather, Birmingham Solar Oscillations Network, BiSON, solar dynamics, asteroseismology, solar dynamo