Date: Thursday, August 28, 2025

Time: 12:30 PM to 1:45 PM

Location:CHTM, Room 103 and Zoom

https://us02web.zoom.us/j/84683488838?pwd=TSag45GDSSuEbv24HBCxIYxlow6QYY.1

Passcode: 833146

Speaker:Dr. Caitano da Silva, New Mexico Tech

Abstract:

On a June afternoon in 1752, dark clouds gathered over Philadelphia. As rain fell and lightning threatened, most citizens sought shelter — but not Benjamin Franklin. For him, it was the perfect time to fly a kite. More than two centuries later, the electrical nature of thunderstorms still challenges scientists. At New Mexico Tech’s Langmuir Laboratory for Atmospheric Research, perched atop the Magdalena Mountains in central New Mexico, our team builds on Franklin’s courage and ingenuity. We study lightning with a suite of instruments that capture its signatures across the entire electromagnetic spectrum — from radio waves to visible light to gamma rays. Our work takes us up close — by deliberately triggering lightning. Using a rocket launched into a thundercloud, tethered to the ground by a copper wire, we create controlled discharges for detailed study. These experiments reveal lightning as a complex, non-equilibrium atmospheric plasma, displaying rich collective behaviors: including several types of ionization waves (streamer, stepped, and dart leader fronts, and return strokes), the ability to accelerate runaway electrons, and negative differential resistance. The plasma nature of lightning results in several complex phenomenological features, including its fractal structure, the contrasting behavior of positively- and negatively-charged extremities, the fact that leader channels are enveloped by streamer zones and corona sheaths, and multiple forms of nonlinearity and hysteresis. The physics of lightning has far-reaching consequences: altering atmospheric chemistry, igniting wildfires, and damaging critical infrastructure such as power transmission systems and wind turbines. In this talk, we present an overview of how the Langmuir Lab team combines in-situ measurements — often with creative, “MacGyver-esque” instrumentation —and physics-based modeling to deepen our understanding of lightning plasma physics.

Biography:

Dr. Caitano da Silva joined New Mexico Tech in 2018, where he is currently an Associate Professor of Physics. He earned his Ph.D. in Electrical Engineering from Penn State University in 2015. His ongoing NSF CAREER award focuses on the development of physics-based, computationally efficient, and data-informed models to advance the understanding of lightning and its impacts. He has authored more than 30 articles on the research topics of lightning, atmospheric electricity, plasma discharges, electrical coupling of atmospheric regions, transient luminous events, and waves in plasmas.