Mechanisms of efficiency enhancement in gyrotron backward-wave oscillators with tapered magnetic fields.

Abstract

Efficiency enhancement in a gyrotron backward-wave oscillator through magnetic field tapering is investigated using computer simulations. The results reveal that the magnetic field tapering with a positive gradient tends to increase the initial frequency mismatch and thus lengthen the confinement of most of the electrons in the energy losing phase, therefore resulting in higher net energy transfer to the wave