Title: Lightning: More Than Meets The Eye
Lecturer: Professor Steven Cummer（Electrical and Computer Engineering, Duke University）
Time: Monday October 20, 2025 at 2:00 PM
Venue: Lecture Hall D103, School of Atmospheric Sciences
Abstract: Over the past 30 years, a wide range of previously unknown phenomena produced by lightning and atmospheric electrical processes have been discovered. Some of these are visible to the human eye if you are lucky enough to be in the right place at the right time, such as gigantic jets that launch from the tops of thunderstorms to 90 km altitude at the edge of space. Others are not visible but are just as impressive, such as terrestrial gamma-ray flashes that beam an intense, short burst of high energy photons, electrons, and even antimatter (in the form of positrons) upward into space and sometimes down towards the ground. And the physics of lightning initiation and development itself is much more complicated than we knew even just 5 years ago. Many of these discoveries all owe thanks to modern radio and optical instrumentation that have delivered images, movies, and measurements with exquisite space and time resolution. In this presentation, I will describe the history of how some these phenomena were first documented and also describe some of the most recent findings that have emerged from ever-improving radio interferometric imaging of lightning and from high altitude measurements of thunderstorm- and lightning-generated gamma rays.
Brief introduction to the speaker: Dr. Steven A. Cummer is the William H. Younger Distinguished Professor of Electrical and Computer Engineering at Duke University. He received B.S., M.S., and Ph.D. degrees in Electrical Engineering from Stanford University, and after 2 years as a postdoctoral fellow at NASA Goddard Space Flight Center, he joined Duke as an Assistant Professor in 2000. His research spans a range of topics in space and atmospheric remote sensing, lightning physics, and engineered electromagnetic and acoustic metamaterials, and he has published more than 300 peer-reviewed journal papers in these areas. Dr. Cummer is a Fellow of the American Geophysical Union and the Institute of Electrical and Electronics Engineers. He is a Clarivate Highly Cited Researcher, and he received a Presidential Early Career Award for Scientists and Engineers (PECASE) in 2001. At Duke his research and teaching have been recognized through the Capers and Marion McDonald Award for Excellence in Teaching and Research in 2009 and the Stansell Family Distinguished Research Award in 2018.