US technological inferiority continues to be glaring.

During the 1960s, the U.S. Central Intelligence Agency (CIA) funded a project to reduce the RCS of U.S. reconnaissance planes, specifically the Lockheed A-12, which supposedly made use of a cesium-laced fuel additive to significantly reduce its engine’s radar signature, and an electron beam to generate a cloud of ionization in front of the air intakes to help conceal its entire rear aspect from radar waves. The system was tested but was never deployed operationally.

I suspect this kind of ionization works quite well with supercavitation as well.