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Indirectly Measured Ambient Electric Fields for Lightning Initiation in Fast Breakdown Regions
Author(s) -
Cummer Steven A.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl086089
Subject(s) - electric field , lightning (connector) , thunderstorm , physics , atmospheric electricity , computational physics , field (mathematics) , electron avalanche , moment (physics) , environmental science , meteorology , ionization , ion , classical mechanics , power (physics) , mathematics , quantum mechanics , pure mathematics
We report a new approach to measure indirectly the ambient thunderstorm electric fields in fast positive breakdown regions. For a given geometry of the discharged fast breakdown region, we show that there is a minimum ambient electric field required to produce a given charge moment change. We apply this approach to the fast breakdown measurements for two events reported by Rison et al. (2016, https://doi.org/10.1038/ncomms10721 ) and find that the average ambient electric field in the discharged region is at least 1 . 0 − 1 . 5 × 1 0 5 V/m at the 9.5 km initiation altitude of these events. This electric field is close to the runaway electron avalanche electric field and to the critical field for positive streamer propagation. These measurements provide a meaningful starting point for more detailed analyses or simulations of what occurs inside the fast breakdown process that is responsible for the initiation of at least some lightning discharges.