I am reminded that Edison invented the thermionic valve, the vacuum tube, but didn’t know it. He was trying to perfect the incandescent electric light and added another wire to the evacuated globe. Electric lighting was a big deal but radio and electronics in time were major too. Edison didn’t get sidetracked though, he kept his focus on lighting. So Fleming gets the credit for the first radio tube, a diode.
Shouldn’t the thrust be much greater with a lopsided superconducting cavity and higher power levels? Is anyone working on this?