HR: 08:00h
AN: AE41A-01 INVITED     [Abstracts]
TI: Do Extensive Air Showers of Cosmic-Ray Secondaries Initiate Lightning, and If So, How Would We Know?
AU: * Beasley, W H
EM: whb@ou.edu
AF: School of Meteorology, University of Oklahoma, Norman, OK 73019 United States
AU: Roussel-Dupre, R A
EM: rroussel-dupre@lanl.gov
AF: Los Alamos National Laboratory, EES-2, Los Alamos, NM 87545 United States
AU: Soluk, R
EM: soluk@phys.ualberta.ca
AF: Centre for Subatomic Research, University of Alberta, Edmonton, AB T6J 2N5 Canada
AU: Eack, K B
EM: keack@nmt.edu
AF: Department of Physics, New Mexico Institute of Mining and Technology, Socorro, NM 87801 United States
AB: The primary source of ionization in the atmosphere below approximately 50 km altitude is energetic penetrating radiation from extraterrestrial sources, known as cosmic rays. Runaway electron theory suggests that the electron population produced in this process can serve as seeds for initiation of electrical discharges when strong electric fields such as those generated in and above thunderstorms are present. We undertake an examination of the possibility, suggested explicitly by a few and accepted implicitly by many, that cosmic rays initiate lightning. The development of a strong measurable discharge depends not only on the availability of seed electrons but also on the fundamental nature of the discharge mechanism itself. Recent theoretical work, such as that of Gurevich, Milikh, and Roussel-Dupre (1992) and recent observations of X-ray emissions during times of observed elevated electric fields in thunderstorms, such as those by Eack et al. (1996) suggest that the combination of ionization by cosmic-rays and runaway breakdown may well be responsible for initiating electrical discharges in thunderstorms as suggested by Gurevich, Zybin, and Roussel-Dupre (1999). We set out to see if existing cosmic-ray observations in conjunction with lightning location data could provide suitable tests of that hypothesis. It turns out that co-located arrays of cosmic-ray detectors and lightning location systems are not necessarily sufficient because of the variability of the spatial distribution and orientation of extensive air showers with respect to active thunderstorm regions. However, we now have an idea of the requirements for observations that could test runaway breakdown hypotheses for initiation of lightning by cosmic rays.
DE: 3324 Lightning
DE: 3394 Instruments and techniques
DE: 2104 Cosmic rays
DE: 3304 Atmospheric electricity
DE: 0600 ELECTROMAGNETICS
SC: Atmospheric and Space Electricity [AE]
MN: 2004 AGU Fall Meeting