X-Ray Emission Associated with Collision of Opposite-Polarity Streamers at the Onset of the Breakthrough Phase of the Lightning Attachment Process
Abstract
Observations of X-ray emissions in natural lightning at the onset of the breakthrough phase (BTP) are very rare. First, we present data for such an event that occurred near the Lightning Observatory in Gainesville (LOG), Florida, then we compare our observations with similar data for lightning events previously reported by Howard et al. (2010), and finally we compare X-ray emissions associated with collision of opposite-polarity streamers observed in lightning and in laboratory sparks. The flash to be discussed in detail occurred on May 25, 2014 and contained five negative strokes. The second stroke created a new ground termination; that is, the lower portion of its leader did not follow the first-stroke channel, while other subsequent strokes developed in a previously-formed channel. The first, second, third, and fifth strokes produced X-rays. Leaders of Strokes 1, 2, and 3 produced 7, 1, and 1 X-ray pulses respectively, some of which were associated with steps, but none occurred at the beginning of BTP. Thus, in this flash only one stroke (the fifth) had BTP whose onset was marked by detectable X-ray emission, and that emission was produced in warm, low-density air, not in cold air in which BTP of Strokes 1 and 2 had to develop. In the fifth stroke the leader steps did not produce detectable X-rays, while the collision of opposite-polarity streamers did, which is exactly the opposite of what we observed for the other three X-ray producing strokes in this flash.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMAE44A..04K
- Keywords:
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- 3304 Atmospheric electricity;
- ATMOSPHERIC PROCESSES;
- 3324 Lightning;
- ATMOSPHERIC PROCESSES;
- 4301 Atmospheric;
- NATURAL HAZARDS