Premium
Modeling of X‐ray Images and Energy Spectra Produced by Stepping Lightning Leaders
Author(s) -
Xu Wei,
Marshall Robert A.,
Celestin Sebastien,
Pasko Victor P.
Publication year - 2017
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2016jd026410
Subject(s) - physics , lightning (connector) , monte carlo method , rocket (weapon) , scattering , computational physics , thunderstorm , optics , meteorology , aerospace engineering , power (physics) , statistics , mathematics , quantum mechanics , engineering
Abstract Recent ground‐based measurements at the International Center for Lightning Research and Testing (ICLRT) have greatly improved our knowledge of the energetics, fluence, and evolution of X‐ray emissions during natural cloud‐to‐ground (CG) and rocket‐triggered lightning flashes. In this paper, using Monte Carlo simulations and the response matrix of unshielded detectors in the Thunderstorm Energetic Radiation Array (TERA), we calculate the energy spectra of X‐rays as would be detected by TERA and directly compare with the observational data during event MSE 10‐01. The good agreement obtained between TERA measurements and theoretical calculations supports the mechanism of X‐ray production by thermal runaway electrons during the negative corona flash stage of stepping lightning leaders. Modeling results also suggest that measurements of X‐ray bursts can be used to estimate the approximate range of potential drop of lightning leaders. Moreover, the X‐ray images produced during the leader stepping process in natural negative CG discharges, including both the evolution and morphological features, are theoretically quantified. We show that the compact emission pattern as recently observed in X‐ray images is likely produced by X‐rays originating from the source region, and the diffuse emission pattern can be explained by the Compton scattering effects.