Is relativistic runaway a significant way thunderclouds lose charge?
In plain words
Many storms glow faintly in gamma rays for seconds to minutes. If the electron avalanches behind the glow carry enough current, they could be a hidden way that clouds discharge besides lightning.
Precise statement
Determine the fraction of thundercloud charging current dissipated by relativistic runaway electron avalanches (gamma-ray glows and flickering flashes) versus lightning, and whether avalanches limit the maximum cloud field near the runaway threshold. An answer is a measured or modeled current ratio constrained by airborne gamma flux and field measurements.
What would settle it
Airborne gamma-ray and electric-field measurements over storm lifetimes combined with avalanche transport models.
Status in the literature
Unverified note
Airborne campaigns reported in 2024 (Marisaldi and coauthors, Nature, https://doi.org/10.1038/s41586-024-07936-6) found gamma emission in tropical storms to be common and highly variable.