Physics Ph.D. student receives prestigious NASA fellowship

Monday, May 04, 2026 • Greg Pederson :

A doctoral student in physics at The University of Texas at Arlington has been selected for a prestigious fellowship to fund his NASA-relevant research.

Tapendra Sodari, a third-year Ph.D. student, was awarded a Future Investigators in NASA Earth and Space Science and Technology (FINESST) fellowship from the NASA Science Mission Directorate (SMD). The award is funded at $50,000 a year for three years.

Sodari’s project, titled “Morphology of Equatorial Ionization Anomaly: GOLD Observations and GITM-SAMI3 Simulations,” is in the SMD’s Heliophysics Division. It examines a major feature of Earth’s upper atmosphere called the Equatorial Ionization Anomaly, which can strongly influence GPS accuracy, satellite operations, and radio communications in equatorial and low latitude regions.

“I am genuinely thrilled and honored to be selected for this award,” Sodari said. “FINESST is highly competitive, with roughly an 18 percent selection rate in Heliophysics this year, so it is exciting and encouraging to receive this recognition.”

Sodari’s faculty mentor is Zihan Wang, UTA assistant professor of physics. Wang’s research interests include numerical modeling of geospace, magnetosphere-ionosphere-thermosphere coupling, and application of machine learning in space weather.

“Tapendra is an outstanding Ph.D. student who is always fully motivated and energetic,” Wang said. “His achievement highlights both his exceptional research potential and the strong national standing of UTA physics students.”

The ionosphere is the portion of the Earth’s upper atmosphere extending roughly 50 to 400 miles above Earth’s surface. It has layers which vary in density based on solar radiation. In the low-latitude and equatorial ionosphere, electrically charged particles, called plasma, form two distinct density bands, or crests, on either side of a low-density trough near the magnetic equator. This structure is known as the Equatorial Ionization Anomaly, or EIA.

“During geomagnetically disturbed periods, these bands can shift, weaken, or intensify,” Sodari said. “Such changes alter electron density along signal paths, degrading GPS positioning accuracy and disrupting radio communications.”

In his research, Sodari is using data from NASA’s Global-scale Observations of Limb and Disk (GOLD) mission, which was launched in 2018. GOLD is an imaging instrument housed on a communications satellite in geostationary orbit which observes the ionosphere and thermosphere. He will combine the data from GOLD with two state-of-the-art models: the Global Ionosphere Thermosphere Model (GITM), a three-dimensional numerical model used to simulate the Earth’s coupled ionosphere and thermosphere; and SAMI3, a three-dimensional model of the ionosphere/plasmasphere system.

“By comparing observations with model simulations, I study how the shape, behavior, and evolution of the post-sunset EIA crests vary with longitude, local time, and geomagnetic conditions. The goal is to understand the physical processes that drive these variations,” Sodari said.

Sodari, a native of Nepal, received his bachelor’s degree in physics from Tribhuvan University in Kathmandu in 2020. He developed an interest in space physics when he took some courses related to space science and attended a workshop on space weather during his undergraduate studies.

“I was always drawn to questions about Sun-Earth interaction, and how the processes occurring in interplanetary space can affect our planet’s upper atmosphere and ionosphere,” he said. “That interest grew stronger as I learned more about the ionosphere and its observations using satellite and ground-based instruments, along with modeling approach.”

Sodari started his doctoral studies at UTA in August 2023. He said he chose UTA because of its strong research program in space science and the opportunity to work with faculty conducting magnetosphere-ionosphere-thermosphere coupling and geospace modeling. He hopes his research will contribute to a better understanding of how Sun-Earth interactions can affect technology on Earth and in space.

“Improving our understanding of the EIA is essential for advancing space weather prediction and protecting critical space-based and ground technologies, making Tapendra’s research both scientifically important and societally relevant,” Wang said.

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