Umran Inan has achieved exceptional success and impact in all facets of his career: scientific research, mentoring and teaching, and leadership. Each on its own is impressive, but when considered together, it is difficult to imagine a more deserving awardee of the 2023 AGU Fleming Medal.

Umran’s scientific accomplishments include key theoretical advances in space and atmospheric physics, such as the theory of wave-particle interactions underlying energetic particle precipitation, which is a significant loss process for planetary radiation belts, and the theory of nonlinear modification of the ionosphere by natural and man-made electromagnetic waves, which plays an important role in lightning-driven transient luminous events in the mesosphere called sprites and in the injection of very low frequency (VLF) electromagnetic waves into the magnetosphere by modulated heating of the ionosphere with high-frequency waves.

Remarkably, Umran is perhaps even better known for his ambitious and innovative experimental work. One example is the continent-scale network of VLF receivers he set up to trace out, for the first time, the size and shape of small- and medium-scale perturbations of the underside of the ionosphere caused by scattering of radiation belt electrons. Umran continued the Stanford tradition of playing a lead role in Antarctic research and worked with virtually every major satellite mission touching on radiation belt physics such as the Air Force DSX satellite, NASA’s Van Allen Probes and the European Space Agency/NASA Cluster satellite constellation.

Furthermore, Umran stands out for outstanding mentoring of students and postdocs. During his career he supervised 60 Stanford Ph.D. students, many of whom went on to leadership positions in academia, industry and government. At least 10 of his former students are professors at top universities across the U.S., and between them they carry on and expand the research he pioneered at Stanford. It is not an exaggeration to say that Umran is personally responsible for space physics being represented at significantly more universities than it would be without him.

Umran has served the broader community for many years through a range of leadership positions, including the international vice-presidency of the International Union of Radio Science (URSI). His commitment to leadership and service eventually led him to a 12-year term as president of Koç University in Istanbul, where he continues in a senior advisory role.

Umran’s impact, in the broadest sense, on the fields in which he has worked is enormous and will continue to be felt for years to come. He truly deserves recognition as the 2023 AGU Fleming Medalist.

— James LaBelle
Dartmouth College
Hanover, New Hampshire

I am truly honored to be the 2023 recipient of the AGU John Adam Fleming Medal, carrying the name of the pioneering geophysicist interested in the magnetosphere and atmospheric electricity well before our time, and humbled by the list of so many outstanding past recipients, including Eugene Parker, Ian Axford and James Van Allen himself. My life in the United States started when I arrived at Stanford for a Ph.D. in electrical engineering as a 22-year-old electrical engineer wannabe knowing nothing about geophysics or space physics. However, I was quickly mesmerized by the intricacies and exciting complexity of the physics of whistler mode wave-particle interactions and lightning-induced effects in near-Earth space and ended up spending 50 years studying these interactions and their effects on the ionosphere and the radiation belts. In my first 10 years at Stanford, I was lucky to be advised by great mentors: my Ph.D. adviser, Robert Helliwell, and senior members of the Stanford VLF Group, Tim Bell and Don Carpenter, all outstanding human beings. Over the next 25 years I was privileged to lead the VLF Group, providing an excellent environment for my former mentors and greatly enjoying my work with a truly outstanding cadre of Ph.D. students. I consider my greatest career achievement to be the graduation of my 60 Ph.D. students, 16 of whom are currently pursuing academic careers, with many active in near-Earth space physics, while others are continuing careers in the aerospace industry. I am truly grateful to and proud of each of them. I attended AGU Fall Meetings for 32 years, from 1976 to 2008. Each one was a huge event for the Stanford VLF Group, with at least 10 presentations at various sessions, all multiply rehearsed for days before the week of the meeting, culminating with an informal dinner at my house, attended by more than 100 colleagues (150 in 2008!) from around the world who made the effort to attend. The secret behind my career is the love of my life for 50 years, my dear wife, Elif Inan. She has always had my back, despite a very busy career of her own, as I worked for too many hours a day and traveled the world for too many days away from home. I am also truly grateful for and proud of our greatest lifetime achievement, our wonderful children, Ayşe and Ali, and our wonderful grandchildren, Ayla, Nisa, and Alim, and the immense joy they bring to our lives.— Umran Inan, Koç University, Istanbul, Türkiye Stanford University, Stanford, California