Tejaswini Rajamahanthi: how a young Indian physicist is learning to read solar storms

Some scientific careers begin inside the corona of a star and arrive, years later, in the ionosphere of a planet. Tejaswini Rajamahanthi is building hers in exactly that direction. A young physicist still in training and currently completing her MSc work in solar and heliospheric physics, she spends her days reconstructing the structure and evolution of coronal mass ejections from SDO/AIA imagery, applying EUV imaging, running-difference analysis and GCS modeling to figure out where solar eruptions are headed and how fast. She also works on X-class flares, on the response of Earth’s ionosphere through GNSS-derived TEC and VTEC measurements, and on the messy, complicated reality of how all that solar activity reaches down to rearrange the upper atmosphere of the planet we live on. Her internship at ISRO’s Vikram Sarabhai Space Centre gave her direct contact with what is probably the most consequential question in modern space-weather research: how exactly does the Sun touch the Earth.

We chose Tejaswini for this Dialogue not because she has decades of papers behind her, but precisely because she does not. Hers is the voice of a generation of researchers stepping into solar and heliospheric science at a moment when the field is being reshaped from many directions at once: by Aditya-L1, Parker Solar Probe and Solar Orbiter; by ground-based facilities of unprecedented resolution; by the slow recognition that space weather is no longer an academic curiosity but a planetary infrastructure problem. India in particular is becoming a serious node of this new science, and the early-career researchers being trained there now will shape what heliophysics looks like twenty years from now. This conversation is offered as an honest snapshot of where such a journey actually begins: the curiosity, the instruments, the data, the doubts, and the long road ahead.

The interview

Conducted in writing by Homer Dávila.

What first inspired your interest in physics, and how did that interest gradually lead you toward solar physics, heliospheric physics, and space-weather studies?

My journey into the world of physics started with a simple curiosity about how everything works in nature, machines, and the universe around us. I’ve always been captivated by astronomy, and I owe a lot to my physics teachers in school for inspiring me to take this subject to heart. Each of my internships, from studying space debris to delving into GNSS and ionospheric research, helped me uncover the fascinating Sun-Earth connection. That exploration naturally drew me toward solar physics, heliospheric physics, and the exciting realm of space-weather studies.

«Unlike flare radiation, which reaches us in just minutes, CMEs take hours or even days to arrive. This gives us some time to study and anticipate their effects»

You are currently specializing in solar and heliospheric physics. What aspects of the Sun and its eruptive activity do you find most scientifically fascinating?

What really amazes me about the Sun is its incredible power and dynamism. Solar flares and coronal mass ejections release immense amounts of energy, and it is astonishing to think that events happening about 150 million kilometres away can significantly impact our planet’s atmosphere, satellites, and communication systems. I am particularly fascinated by the plasma physics and magnetic processes that drive these eruptions, and by how they travel through the heliosphere on their way to us.

Your MSc research involves the analysis of coronal mass ejections using SDO/AIA data and in-situ observations. Could you explain, in broad terms, why CMEs are so important for understanding the Sun-Earth connection?

CMEs are crucial because they significantly influence space weather. They carry massive amounts of plasma and magnetic field from the Sun into the vastness of space, and when they interact with Earth’s magnetosphere they can spark geomagnetic storms and disrupt the ionosphere. Unlike flare radiation, which reaches us in just minutes, CMEs take hours or even days to arrive. This gives us some time to study and anticipate their effects, making them vital for both research and space-weather forecasting.

In your current work, you use techniques such as EUV imaging, running-difference analysis, and GCS modeling to study the structure and evolution of CMEs. How do these tools help researchers reconstruct the behavior of solar eruptions?

The techniques we use to track CMEs from their origin on the Sun to their journey through space are genuinely fascinating. EUV imaging helps us spot features such as filament eruptions and flares, while running-difference analysis makes it easier to observe the movement of the CME itself. GCS modeling allows us to reconstruct these CMEs in three dimensions and to estimate key parameters such as speed, direction, height and tilt, all of which are essential for understanding the potential impact on Earth.

«That experience really made the Sun-Earth connection come alive for me »

You are also working on X-class solar flare events. What makes these powerful flares especially important in solar physics and space-weather research?

X-class flares are particularly interesting because they are the most energetic type of solar flare and can significantly influence our space environment. They can cause radio blackouts, interrupt navigation and communication systems, and often accompany major CMEs and high-energy particle events. Studying these flares helps us unlock the mysteries of extreme magnetic-energy release and particle acceleration in the solar atmosphere.

6. Your work extends into the ionosphere-GNSS domain, including TEC and VTEC estimation using RINEX and ISMR data. How can GNSS observations help us understand the response of Earth’s ionosphere to solar and geomagnetic activity?

GNSS observations are extremely useful for studying changes in the ionosphere because they allow us to estimate Total Electron Content (TEC) and Vertical TEC (VTEC), which tell us about the electron density in Earth’s upper atmosphere. During solar eruptions and geomagnetic storms the ionosphere can become quite chaotic, and we can see those changes clearly in GNSS data. By examining these variations across different latitudes and during a range of solar events, we gain a much deeper understanding of how Earth’s atmosphere reacts to solar activity.

During your internship at ISRO’s Vikram Sarabhai Space Centre, you analyzed ionospheric plasma dynamics during geomagnetic storms using solar wind and IMF data. What did that experience teach you about the relationship between solar activity and near-Earth space?

During my internship at ISRO’s Vikram Sarabhai Space Centre I got a real sense of how interconnected the Sun and Earth truly are. By analyzing solar wind, interplanetary magnetic field and ionospheric data during geomagnetic storms, I could see firsthand how changes in solar activity affect Earth’s magnetosphere and ionosphere. That experience really made the Sun-Earth connection come alive for me and deepened my passion for heliophysics and space-weather research.

«Every new paper or dataset feels like opening the door to a new adventure»

You have worked with both observational data and physics-based modeling. In your view, why is it important to combine observations, data analysis, and modeling when studying space plasma environments?

I believe that combining observations, data analysis and modeling is the only way to paint the full picture. Observations reveal what is happening in real time, data analysis helps us identify patterns and relationships, and models explain the physics behind those observations. Together, they enhance our understanding of space plasma environments and make space-weather predictions much more reliable.

As a young researcher entering solar and heliospheric physics, what have been the most important challenges and learning experiences in your academic path so far?

One challenge I face as a young researcher is the constant need to learn new concepts in this wide-ranging and interdisciplinary field. Sometimes it is tough to find the right opportunities and to decide on the best direction for future research. But every new paper or dataset feels like opening the door to a new adventure. The more I explore solar eruptions and Earth’s responses, the more questions and connections I uncover. It is this curiosity that keeps me genuinely excited about the field.

Looking ahead, what research questions would you like to explore in the future, and how do you hope to contribute to solar physics, heliophysics, or space-weather science in the coming years?

Looking ahead, I am eager to study different types of solar eruptive events, including flares, CMEs and prominences, and to explore how they influence Earth’s ionosphere and TEC across various latitudes. I want to combine multi-spacecraft observations with modeling to better understand the physics driving these eruptions and to improve our prediction methods. I would also love to extend this research to other planets such as Mars and Venus, to see how stellar activity affects their environments as well.

Editorial reflection

There is something genuinely refreshing about reading a scientific career while it is still being assembled in real time. Tejaswini’s answers do not carry the gravity of a forty-year retrospective, and they shouldn’t. That is not where she is, and that is not what this Dialogue is for. What they do carry is something arguably more useful for the readers SKYCR cares about most: a clear, honest window into how someone exactly one or two steps ahead of an undergraduate physics student is actually entering modern solar and heliospheric research.

The instruments she names are accessible. The methods she describes are learnable. The questions she finds exciting are the same questions occupying senior researchers around the world. The distance between a curious eighteen-year-old in San José, Lima, Bogotá or Madrid and the kind of work Tejaswini is doing today is shorter than it looks from the outside. That, in the end, is the point of this Dialogue: not to anoint a finished scientist, but to make visible what the early ladder of this field actually looks like, and who is climbing it right now.

By Homer Dávila Gutiérrez, FRAS.