Physics doctoral student wins award for research on space weather's differing effects on Earth's hemispheres
A doctoral student in space physics at The University of Texas at Arlington earned high accolades for his research project about the differing effects on Earth’s northern and southern hemispheres caused by the interaction between the Sun and Earth.
Yu Hong received first place in the poster competition at the 2022 CEDAR (Coupling, Energetics and Dynamics of Atmospheric Regions) Workshop, an international conference held June 19-24 in Austin. His work was selected as the best among entrants from 20 countries. Hong is a third-year Ph.D. candidate whose advisor is Yue Deng, UTA distinguished professor of physics.
His poster is titled “Inter-hemispheric asymmetry of the ion-convection boundary expansion during the 8-10 October 2012 storm.” The results have been summarized into a manuscript which Hong and his co-authors plan to submit for publication in the journal Frontiers in Astronomy and Space Sciences.
“I was super surprised about winning because this was my first time attending the poster competition as well as the CEDAR workshop in person,” Hong said. “I've seen a lot of excellent posters and I knew it would be very competitive.”
The research utilized high-latitude patterns from AMIE (Assimilative Mapping of Ionospheric Electrodynamics) to drive the global ionosphere–thermosphere model (GITM) for examining the geospace response in the ionosphere-thermosphere (I-T) system during a geomagnetic storm that occurred from October 8-10, 2012. Geospace is the region of outer space near the Earth and is the domain of Sun-Earth interactions.
This summer, Hong is visiting the National Center for Atmospheric Research (NCAR) as part of its highly selective Graduate Visitor Program. The three-month program runs through August and supported by the NCAR Advanced Study Program fellowship. Hong is working with Astrid Maute, a project scientist at the NCAR High Altitude Observatory, developer of the NCAR 3D-electrodynamo model (NCAR-3D) and one of Hong’s co-authors since the first year of his Ph.D. studies.
“Two sources of the storm-time equatorial electric fields are the penetration electric field and the disturbance neutral wind dynamo,” Hong said. “The NCAR-3D can solve the wind dynamo physically for the upper atmosphere, but how to better handle the penetration electric field in models is still a challenging issue to our geospace community.
“With both radar and satellite data as well as the GITM and NCAR-3D framework, we are working on the low-latitude electrodynamics, and the hemispherically asymmetric storm-time responses in that region.”
Hong was born in Shandong province, China and first took an interest in physics in high school, when he had the opportunity to participate in a Physics Olympics competition study, which gave him an access to college physics and math knowledge.
“This learning experience benefited me a lot and developed a physical thinking ability, thus I decided to study physics at university,” Hong said.
He went on to study space physics at the University of the Chinese Academy of Sciences and GFZ German Research Centre for Geosciences. In 2017, he attended the Peking University Space Weather Summer School, where Deng presented a lecture.
“I talked to Yue at that time; she is an exceptional scientist and has a strong understanding of all aspects of the space physics fields,” Hong said. “It was also my first exposure to numerical simulation, which is quite different from the data analysis I did before. I thought it would be exciting to learn modeling simulations during my Ph.D. period which allows me to better understand the whole physical process.”
He applied to UTA and began the Ph.D. program in fall 2019 with Deng as his mentor. In his doctoral studies, Hong is working to understand why Earth’s upper atmosphere responds to space weather effects so differently in the two hemispheres.
“Our current understanding of the geospace relies on an outdated assumption that our northern and southern hemispheres are symmetrically affected by physical processes related to the Sun-to-Earth interaction, but this is not the real case,” he said. “We are working on how and why the two hemispheres are affected differently, which is known as the inter-hemispheric asymmetry. Many causes contribute to these asymmetries, such as season-related solar irradiance flux, the high-energy particle precipitation and electrodynamic energy dissipation in the auroral regions, and the asymmetric geomagnetic field configuration between the two hemispheres.”
Hong was lead author of a paper published in the October 2021 edition of the journal Space Weather titled “Impacts of Different Causes on the Inter-Hemispheric Asymmetry of Ionosphere-Thermosphere System at Mid- and High-Latitudes: GITM Simulations.” Deng co-authored the study, along with other members of the UTA Department of Physics.
“Yu is a talented and self-motivated graduate student,” Deng said. “He has a strong desire to solve important science problems. His recent publication in the Space Weather journal strongly improves our understanding of the relative importance of different mechanisms to the inter-hemispheric asymmetry in the ionosphere-thermosphere system.”
Hong’s research is a part of the NASA Phase I DRIVE Science Center program. UTA is leading the CUSIA (Center for the Unified Study of Interhemispheric Asymmetries) team project, which brings together experts on the Earth’s atmosphere and outer space to collaborate and update the scientific tools that are needed to study inter-hemispheric asymmetry. The project’s ultimate goal is to improve the ability to predict the effects of space weather on humans. Meanwhile, it will be part of the Geospace Dynamic Constellation (GDC) Interdisciplinary Scientist (IDS) project, which will support the GDC satellite mission’s launch, operations and closure of science goals.
“Without including the inter-hemispheric asymmetries, we can’t fully understand the whole process between the Earth’s upper atmosphere and the Sun,” Hong said.
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