China conducts test flight of a giant coil array. Can it detect nuclear submarines?

China has conducted a test flight of a large coil array system, identified as Airborne Transient Electromagnetic (Atem) detection. During the test at an undisclosed site, a helicopter towed the kite-like array. The Atem system operates by sending a powerful electrical pulse through a large transmitter coil, generating a strong electromagnetic field that can penetrate the ground or water. When the pulse ceases, this field induces eddy currents in conductive materials. These eddy currents then produce their own secondary magnetic field, which is detected by a receiver coil. The article does not explicitly state the purpose of this test or whether it is intended to detect nuclear submarines.