Yup, the whole sub structure is a shield, as it's made from steel, which is ferromagnetic. Also the 20T field is only in the "air gap" of the drive. I think on

Yup, the whole sub structure is a shield, as it's made from steel, which is ferromagnetic. Also the 20T field is only in the "air gap" of the drive. I think one needs supercomductors to obtain that kind of magnetic field. The PUMP drive would use seawater as the conductive media, which also complicates things with electrolysis and Joule heating near the electrides. I don't know tge geometric configuration of the "air gap" but it could be a copule of milimetres thick in order to put a 20T field through it. See this video explaining how it works on liquid metal. It uses the Lorentz force. https://youtu.be/nakeHnWVUjQ https://youtu.be/nakeHnWVUjQ