Overview

• The Photoelectric Feedback Discharge model published July 28 delivers the first precise quantitative framework for lightning initiation.
• It shows strong electric fields in thunderclouds accelerate cosmic-ray–seeded electrons to emit high-energy X-rays that spawn runaway electron avalanches.
• X-ray–driven photoelectric feedback generates new seed electrons and can produce terrestrial gamma-ray flashes without visible light or strong radio signals.
• Researchers validated the simulations using data from NASA’s high-altitude U-2/ER-2 flights, Kanazawa ground sensors, satellites and other field instruments.
• All model equations and methods are openly published for replication and follow-on studies, backed by funding from NSF, CNES, Institut Universitaire de France and the Czech Ministry of Defense.