A 2-kilowatt multioctave traveling-wave tube focused with samarium cobalt magnets

The most severe and fundamental performance limitation of the PPM focused TWT has been excessive thermal heating of the r-f propagating structure due to some fractional interception of the electron beam. The quality of beam focusing has largely been determined by the characteristics of permanent magnets in the Alnico series. With the introduction of the cobalt rare-earth alloys, a breakthrough in the performance of PPM focused TWT´s can be expected.