Recent research from the Fujian Institute of the Structure of Matter at the Chinese Academy of Sciences unveiled a novel approach for the “detection and tracking” of submarines. This study, titled “Evolution of Electromagnetic Signals from Submarines Under Natural Cavitation,” was published in the Journal of Chinese Naval Research. It caught the attention of the South China Morning Post on the 13th, which remarked on its potential to “threaten U.S. maritime dominance.”
The research reveals that as an object moves through a liquid, it creates a low-pressure zone in its wake because the fluid fills the space left by the moving object. If the object, in this case, a submarine, moves rapidly, the rear water pressure temporarily drops below the saturation vapor pressure. This causes dissolved gases in the water to evaporate, forming tiny bubbles or cavities.
These cavities, when formed around a moving submarine, result in complex turbulence in the surrounding seawater. This turbulence generates electric and magnetic fields. The strength of these signals is potentially 3 to 6 orders of magnitude stronger than that detected by advanced magnetic anomaly detectors and falls within the range of even the most advanced detection instruments currently available. The generated electric and magnetic fields have extremely low frequencies, ranging from 34 to 50 hertz. These frequencies, which are in the very low-frequency radio range, can be reflected back to the ground by the Earth’s ionosphere or detected by instruments thousands of kilometers away. By analyzing the strength and direction of the magnetic field, one can determine the location and trajectory of the submarine.
However, researchers emphasized that this detection isn’t foolproof. The mentioned signals could be generated by other human or natural activities. If a submarine intentionally maintains a low speed to avoid creating these cavities, it would be challenging to detect using this method.
In April, CNN reported remarks by Carl Schuster, the former operations director of the U.S. Pacific Command’s Joint Intelligence Center in Hawaii. He confidently asserted that “the U.S. holds an undisputed advantage over China in submarine capabilities,” emphasizing the striking power, survivability, and stealth of U.S. submarines. Many military analysts have often considered American submarines the “most challenging to detect,” partly due to their sophisticated acoustic and vibration-reducing systems, which integrate them seamlessly into the ocean’s ambient noise, making traditional detection methods ineffective.
Nevertheless, the authors of “Evolution of Electromagnetic Signals from Submarines Under Natural Cavitation” note that no matter the technology or material used, high-speed submarines can’t evade the formation of these cavities. In line with this, the South China Morning Post commented on the 13th that this new discovery poses a “threat to U.S. maritime dominance.”
As per a report from September 2022 in the South China Morning Post, China is developing a supersonic missile capable of both flight and underwater operation. This torpedo can reportedly reach underwater speeds of up to 100 meters per second, making it a deadly threat to any ship or submarine. If both these technologies – the new detection method and the supersonic torpedo – are effectively utilized and combined, it would indeed pose significant challenges for U.S. submarine deployments near Chinese waters. The authors of the study emphasize the need for more precise research to ensure the practical application of this discovery in the real world.