Traveling Ionospheric Disturbances With Huge Semicircular and Circular Structures Triggered by Two Rocket Launches Over China

Abstract Rocket‐launching can trigger traveling ionospheric disturbances (TIDs) which often show V‐shaped structures. Using a dense Global Navigation Satellite System total electron content (TEC) receiver network, we investigated the ionospheric response to the waves triggered by the launches of Long March (LM) series of rockets, the LM‐2D on 30 March 2023 and LM‐6A on 10 September 2023. Results show that during the two launches, large ionospheric holes and TIDs with unusual semicircular and circular structures were observed. The ionospheric disturbances traveled for a distance of more than 1,500 km with amplitudes gradually decreased from about 0.1 to 0.03 TEC unit. The period and horizontal speed of disturbances were ∼7–8 min and around 700–800 m/s, respectively, which fell into the acoustic mode. We suggest that the TIDs were induced by shock acoustic waves (SAWs). The semicircular and circular structures could be attributed to the rocket flight tilt angle and the corresponding altitude of conic SAWs.