A. Lindanger, C.A. Skeie, M. Marisaldi, I. Bjørge-Engeland, N. Østgaard, A. Mezentsev, D. Sarria, N. Lehtinen, V. Reglero, O. Chanrion, and T. Neubert, Production of Terrestrial Gamma-ray Flashes During the Early Stages of Lightning Flashes, EGU General Assembly, Vienna, 23-27 May, 2022