An axially twice acceleration low impedance HPM source

M.J. Arman presented a new low impedance HPM source-Radial Acceletron (1996), it has the following new characteristics: (1) There are very high harmonic currents in the device because it combines the oscillator and the diode into one; (2) The impedance of the diode is very low due to being coaxial, thus allowing larger input and output powers. We try to make two improvements for the device: (1) Add a accelerating section after the diode/ oscillator, make the bunched beam to be accelerated again, then extract the radiation emitted by the bunched and postaccelerated beam in the extraction cavity. Therefore one can not only raise the power and conversion efficiency of the beam, but also select output frequency of the waves. While in the Radial Acceletron, the conversion efficiency is not high enough, and the output frequency can not be tuned; (2) Change the radial acceleration to axial acceleration. In the configuration of radial outward twice acceleration, radius of the cavity should be very large, and the field and beam in it are divergence. In the configuration of radial inward acceleration, the power capacity is very small; While the new configuration of axially twice acceleration does not have these problems. The coaxial axially twice acceletron needs no magnetic guide field like the Super-Reltron. But its modulation cavity is TTO rather than SCO, and compared to SCO, it is not easy to breakdown due to its larger power capacity and the bunching of the beam is much better because of the combining of the oscillator with the diode