EAGER: Observations of High-Energy Radiation from Lightning from a Mobile Platform

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

This research consists of a summer campaign of observing high-energy radiation associated with thunderstorm lightning using ADELE, the Airborne Detector for Energetic Lightning Emissions. ADELE was built with funding from NSF's Major Research Instrumentation program. This study is more in an exploratory nature, and requires expeditious deployment of the research team and instruments to the field in this coming summer. ADELE will be carried to the vicinity of lightning discharges in a van. The campaign will take place mostly in central Florida, with a preliminary few days of observing at high-altitude sites in New Mexico. Collected data will be analyzed after the field campaign. Intellectual Merit. Relativistic runaway, a process in which high-energy electrons multiply themselves and produce x-rays and gamma-rays when they collide with the atoms of air, occurs at various timescales and conditions in thunderstorms and may be involved in stepped-leader propagation, lightning initiation, and in limiting the maximum electric field attainable in air. Even where the high-energy radiation does not play a controlling role, it can serve as a diagnostic of the field conditions in regions, such as the head of a leader, which are not easily accessible. By taking the instrument to the lightning in real time for the first time, ADELE's campaign should result in a much higher yield of gamma-ray data per day than can be obtained by stationary detectors. The gamma-ray data returned by ADELE will be combined with meteorological data and observations of radio emission by lightning provided by long-term collaborators at Duke University and Los Alamos National Laboratories. Broader Impacts. This research may enhance the understanding of atmospheric electricity, and broaden the society's awareness of thunderstorm lightning activity. We expect this campaign to prove the value of storm-chasing measurements in this field of research and to result in larger programs down the road. The science teams at University of California, Santa Cruz and the Florida Institute of Technology are dedicated to the inclusion of graduate and undergraduate students in NSF-funded research projects, and have long histories of successful student involvement.