Recent ground-based radio-frequency observations have identified a new class of in-cloud lighting discharge called “energetic in-cloud” pulses (EIP). The high peak electric currents of EIP pulses have led to prediction that they might be connected with Terrestrial Gamma-ray Flashes (TGFs). Observations by Wada et al.  confirm this prediction. They move the connection of EIP with TGF from speculation to solid science. This allows for downward TGFs now to be analyzed using radio sensors only, a huge advance since their coverage area is much greater than that of ground-based gamma-ray sensors, hundreds of kilometers versus about two kilometers.
Citation: Wada, Y., Enoto, T., Nakamura, Y., Morimoto, T., Sato, M., Ushio, T., et al. . High peak‐current lightning discharges associated with downward terrestrial gamma‐ray flashes. Journal of Geophysical Research: Atmospheres, 125, e2019JD031730. https://doi.org/10.1029/2019JD031730
—Minghua Zhang, Editor in Chief, JGR: Atmospheres