| Autor: |
Sterpka, C., Dwyer, J., Liu, N., Demers, N., Hare, B. M., Scholten, O., ter Veen, S. |
| Předmět: |
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| Zdroj: |
Geophysical Research Letters; 12/28/2022, Vol. 49 Issue 24, p1-6, 6p |
| Abstrakt: |
We report on ultra‐slowly propagating discharge events with speeds in the range 1–13 km/s, much lower than any known lightning process. The propagation speeds of these discharges are orders of magnitude slower than leader or streamer speeds, but faster than the ion drift speed. For one particular event, a lightning leader forms about 40 ms later within 50 m of the discharge, likely within the same high field region. A second slow event forms 9 ms prior to the initiation, and leads into the negative leader. Most slow events appear to not be directly involved with lightning initiation. This suggests that the classic streamer cascade model of initiation is not always a definitive process. In this work we describe these discharge events displaying unique behavior, their relation to common lightning discharges, and their implications for lightning initiation. Plain Language Summary: While lightning is generally a very fast process, here we report on ultra‐slow discharges which may be a new and unexpected method of lightning initiation. These discharges travel at uncharacteristically low speeds and are observed in conjunction with lightning initiation in two cases, while in three different cases they are not. This indicates that these events are also evidence of failed lightning leader formation, which complicates the current understanding of how lightning initiates. Additionally, the velocity of these events is slow enough that in principle the propagation can be observed by the unaided eye ‐ challenging the colloquial notion of "fast as lightning." Key Points: The ultra‐slowly propagating events travel at speeds at least an order of magnitude slower than the slowest positive leadersIn one observed case, the slow propagation led directly into the formation of a lightning leaderIn most cases, these discharges are not connected with lightning initiation [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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