X-ray emission from natural and triggered lightning
Abstract
We report on x-ray observations of lightning made at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, FL. Using NaI(Tl)/photomultiplier tube detectors housed inside heavy aluminum boxes designed to keep out light, moisture and RF noise, we have measured x-ray emission from nearby natural lightning and rocket-triggered lightning. Electric fields and channel-base currents (for triggered lightning only) were also recorded. The x-ray emission most often occurs during the stepped and dart leader phases with possibly some emission occurring during the very beginning of the return strokes. The energy spectra for both natural and triggered lightning typically extend up to a few hundred keV, and the x-rays arrive in a sequence of discrete bursts, less than 1 microsecond in duration, with the stepped leader emission usually starting approximately 1 millisecond before the return stroke and the dart leader emission usually starting within about 100 microseconds of the return stroke. In this presentation, we will review observations made during the 2002 and 2003 seasons and present new results from the 2004 season, including new x-ray data from several natural lightning strikes. In addition, we will discuss the Thunderstorm Energetic Radiation Array (TERA), currently under construction at the ICLRT.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2004
- Bibcode:
- 2004AGUFMAE41A..03D
- Keywords:
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- 3324 Lightning;
- 3329 Mesoscale meteorology;
- 3359 Radiative processes;
- 3399 General or miscellaneous;
- 3304 Atmospheric electricity