HR: 0800h
AN: AE31A-0048    [Abstracts]
TI: Spatial distribution of X-ray bursts in triggered lightning experiments
AU: * Bakhtiari, M
EM: mbakhtia@fit.edu
AF: Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901,
AU: Saleh, Z
EM: zsaleh@fit.edu
AF: Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901,
AU: Dwyer, J
EM: jdwyer@fit.edu
AF: Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901,
AU: Rassoul, H
EM: rassoul@fit.edu
AF: Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901,
AU: Uman, M
EM: uman@ece.ufl.edu
AF: Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611,
AU: Howard, J
EM: ironjoe@ufl.edu
AF: Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611,
AB: During rocket-triggered lightning experiments, it has been observed that the dart leader phase is accompanied by bursts of X-rays. These experiments were carried out at the University of Florida/Florida Tech International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, FL. We report here the analysis of a sequence of X-ray bursts that occurred during the dart leader of a lightning flash triggered on July 31, 2007. The measurement of the penetrating X-ray photons was done with the Thunderstorm Energetic Radiation Array (TERA), which consists of more than 40 NaI detectors systematically distributed at various distances within 500 m from the launching tower. The integrated observed X-ray intensity at ground level over a short time prior to the return stroke shows a strong radial decay. On the other hand, the integrated radial X-ray distribution is rather flat at earlier times. The measurements are compared with simulations that include the physics of photon propagation through air. The results are consistent with a source that travels from high altitude to near ground level (the top of the rocket launching tower).
DE: 0360 Radiation: transmission and scattering
DE: 3304 Atmospheric electricity
DE: 3324 Lightning
DE: 3359 Radiative processes
DE: 6009 Aurorae, airglow, and X-ray emission
SC: Atmospheric and Space Electricity [AE]
MN: 2007 Fall Meeting