On the Beam Characteristics of X‐Ray Bursts Observed in Rocket‐Triggered Lightning

Abstract Employing the multi‐station Thunderstorm Energetic Radiation Observation System, we detected X‐ray bursts during two rocket‐triggered lightning events in 2024. By innovatively integrating optical imaging with three‐dimensional lightning channel reconstruction based on Distributed Acoustic Sensing (DAS), we analyzed the X‐ray emission characteristics from these events. During the Tl_20240812 event, lateral deflection of a descending negative leader resulted in X‐rays being detected exclusively by a distal sensor. This clear spatial correlation provides direct and conclusive geometric evidence that the radiation is emitted in a beam‐like pattern along the leader propagation path. Furthermore, based on the Tl_20240801 event, this study achieved the first quantitative estimation of the X‐ray photon beam half‐angle width, determined to be between 40° and 46°. This angular range aligns with the predicted structure of the leader tip electric field, thereby providing robust support for the hypothesis that X‐rays originate from the leader tip high‐field runaway electron mechanism.