Using an eight‐station time of arrival (TOA) network composed of NaI(Tl) scintillation detectors and wideband electric field derivative (dE/dt) antennas covering approximately 1 km2 on the ground, we have located both the sources of X‐ray emissions and electric field changes produced during the leader phase of both downward negative natural and rocket‐triggered lightning strokes. We show that the sources of X rays and leader step electric field changes are co‐located in space within 50 m and that the located X rays are emitted 0.1 to 1.3 μs after the origin of the leader step electric field changes.
