Study on Four-Dimensional Evolution of Concentric Traveling Ionospheric Disturbances After Falcon 9 Rocket Launch Using Ionospheric Tomography

The ionospheric disturbances induced by the Falcon 9 rocket launch on 17 January 2016 were reconstructed by three-dimensional computerized ionospheric tomography using observations from the North American global navigation satellite system networks. The results showed that concentric traveling ionospheric disturbances (CTIDs) occurred ∼18 min after the rocket launch and were remarkable at 200–300 km altitudes. The vertical phase velocities of the CTIDs were consistent with the inclinations of the U-shaped structures. At specific azimuth directions of 350°, 30°, and 105°, the estimated vertical phase velocities between 100 and 200 km altitudes were ∼222.2, ∼208.3, and ∼242.4 m/s, respectively. When the CTIDs propagated upward to 400–500 km altitudes, their vertical velocities increased to ∼566.7, ∼966.7, and ∼944.4 m/s. CTIDs traveling northward (azimuths 350°, 30°) had periods of ∼11 min. At 200 and 300 km altitudes, their horizontal phase velocities were ∼309.9–323.3 and ∼309.4–330.9 m/s, respectively, with horizontal wavelengths of ∼204.5–213.4 and ∼204.2–218.4 km. In contrast, CTIDs propagating eastward (azimuth 105°) displayed a period of ∼15 min. At 200 and 300 km altitudes, their horizontal phase velocities were ∼223.2 and ∼241.1 m/s, respectively, with horizontal wavelengths of ∼200.9 and ∼217.0 km. These CTIDs propagation characteristics agreed well with the theory of gravity waves.