Using data from nearly 2,000 ground-based GNSS observation stations, the response of two-dimensional total electron content (TEC) and three-dimensional electron density in the ionosphere during the solar eclipse on April 8, 2024 was investigated. The eclipse resulted in TEC decrease that lasted for over 7 h, covering the entire United States. Approximately 60 % of the obscuration region along the eclipse path experienced TEC depletes ranging from 20-40 %. Following the eclipse, a widespread TEC enhancement was observed, propagating from high-latitude regions towards the equator. After the TEC enhancement, a secondary large-scale TEC depletion phenomenon was observed for the first time, with the depletion belt mainly concentrated near the eclipse path. The TEC enhancement and TEC secondary depletion exhibit distinct variations in latitude and longitude, respectively. The overall three-dimensional electron density in the ionosphere displayed consistent behavior with TEC, but exhibits significant altitude-dependent characteristics. The maximum electron density decrease occurred near the F2 peak at an altitude of 300 km, with a magnitude of up to 30 %. Ionospheric plasma disturbances triggered by the eclipse may be associated with dynamic processes related to plasma flux from the upper ionosphere. |
