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For the first time, geophysicists from China used ground-based radar to observe in real time the formation of equatorial plasma bubbles, which are quite difficult to find with profile instruments. The observation took place at a distance of almost 10 thousand kilometers.
Radar LARID — long-range low-latitude ionospheric radar installed on Hainan Island and has a detection range of 9,6 kilometers. Conventional radars can hardly "catch" targets below the horizon due to the curvature of the planet. LARID overcomes this problem by emitting powerful electromagnetic waves that bounce off the ionosphere and the ground, allowing it to cover long distances.
The Chinese radar operates in the frequency range of 8-22 megahertz and is equipped with two radar subsystems: one directed to the east, the other to the west. Each has 24 receiving and transmitting antennas.
LARID uses a fully digital phased array system that allows for real-time adjustments to detection frequency, range, scan area, and radar tuning as needed.
The Chinese radar has a unique ability. It can detect equatorial plasma plumes, an "abnormal atmospheric phenomenon" that disrupts satellite communication and the GPS system, causing interference in the ionosphere. These plasma bubbles opened a long time ago, they are usually observed in low latitudes. They are formed when a large number of electrons are suddenly ejected from the ionosphere, creating extensive "electron-coupled" zones.
Until now, the observation of these bubbles has been fraught with difficulties. However, LARID coped with the tasks and thus, according to Chinese scientists, became the first radar in the world that managed to detect these anomalies in the atmosphere. When the Chinese radar emits powerful electromagnetic waves, they collide with equatorial plasma bubbles, as a result, part of the signal is reflected back and picked up by the LARID antenna array.
During the solar magnetic storm on November 4-6, 2023, the LARID system successfully detected radar echoes from plasma bubbles forming over North Africa and the central Pacific Ocean. By analyzing these signals, Chinese scientists were able to observe the formation of plasma bubbles and track their movement in real time over the Egyptian pyramids of Giza and the Midway Islands. That is, geophysicists monitored the anomaly at a distance of almost 10 thousand kilometers, an unprecedented detection range. The discovery was reported by the South China Morning Post with reference to the Institute of Geology and Geophysics at the Chinese Academy of Sciences.
Chinese researchers believe that their discovery will be important for global communication and navigation systems, namely, it will allow to mitigate the negative impact of plasma bubbles on satellite signals. In the near future, China may build three to four more LARID-like radars in low-latitude regions. Such a network will provide continuous monitoring of equatorial plasma bubbles in real time.
Due to insufficient resolution, LARID is not suitable for detecting military targets such as fighter jets or ships. However, according to official Chinese media reports, the local military is actively using over-the-horizon radars with technologies similar to those of LARID, which can successfully determine the location of the American F-22 Raptor fifth-generation stealth fighters.
