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dc.contributor.authorSaleh, Ziad H.
dc.contributor.authorDwyer, Joseph R.
dc.contributor.authorHoward, Joseph S.
dc.contributor.authorUman, Martin A.
dc.contributor.authorBakhtiari, Mohammad Reza
dc.contributor.authorConcha, D
dc.contributor.authorStapleton, Michael V.
dc.contributor.authorHill, Dustin
dc.contributor.authorBiagi, Christopher J.
dc.contributor.authorRassoul, Hamid K.
dc.date.accessioned2017-10-20T17:18:55Z
dc.date.available2017-10-20T17:18:55Z
dc.date.issued2009
dc.identifier.citationSaleh, Z., Dwyer, J., Howard, J., Uman, M., Bakhtiari, M., Concha, D., . . . Rassoul, H. (2009). Properties of the X-ray emission from rocket-triggered lightning as measured by the thunderstorm energetic radiation array (TERA). Journal of Geophysical Research Atmospheres, 114(17)en_US
dc.identifier.urihttp://hdl.handle.net/11141/2099
dc.descriptionCharacteristic energy, Energetic electron, Energetic radiation, Energetic source, Florida, Florida Tech, International center for lightning research and testing, Lightning channel, Monte Carlo Simulation, Relativistic runaway electron, Return stroke, RF noise, Rocket launch, Runaway electrons, Stepped leader, Strong electric fields, Triggered lightning, University of Florida, X-ray emission, X-ray propagation.en_US
dc.description.abstractThe Thunderstorm Energetic Radiation Array (TERA) is located at the University of Florida, Florida Tech International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, Florida. The array includes forty-five 7.6-cm-diameter NaI/photomultiplier tube detectors enclosed in 24 separate aluminum boxes that shield the detectors from light, moisture, and RF noise. The array covers the ∼1 km2 ICLRT facility, centered on the rocket launch tower, used to trigger lightning. From 2005 to 2007, TERA recorded seven rocket-triggered lightning flashes. In this paper we present an analysis of the X-ray emission of three of these flashes. The X-ray emission is observed to occur during the dart leader phase of each stroke, just prior to the time of the return stroke. Significant X-rays are observed on all the detectors to a distance of 500 m from the lightning channel for times up to 200 μs prior to the start of the return stroke. Using Monte Carlo simulations to model the X-ray propagation, we find that the energetic electrons that emit the X-rays have a characteristic energy of about 1 MeV for one particular dart-stepped leader event. The X-ray emission for all three events has a radial fall off proportional to [exp (-r/120)]/r and is most consistent with the energetic source electrons being emitted isotropically from the leader. It is also found that the X-ray and energetic electron luminosities of the leader channel decreases with increasing height above the ground. These results help shed light onto the mechanism for producing energetic radiation from lightning. For instance, a characteristic energy of 1 MeV is not consistent with the relativistic runaway electron avalanche mechanism, suggesting that so-called cold runaway electrons, produced by very strong electric fields, dominate the production of the X-rays. Copyright 2009 by the American Geophysical Union.en_US
dc.language.isoen_USen_US
dc.rights© 2009 by the American Geophysical Unionen_US
dc.rights.urihttp://publications.agu.org/author-resource-center/usage-permissions/#repositoryen_US
dc.titleProperties of the X-ray emission from rocket-triggered lightning as measured by the Thunderstorm Energetic Radiation Array (TERA)en_US
dc.typeArticleen_US
dc.identifier.doi10.1029/2008JD011618


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