EXPERIMENTAL DEMONSTRATION OF HIGH-EFFICIENCY ELECTRON-CYCLOTRON AUTORESONANCE ACCELERATION

First experimental results are reported on the operation of a multimeg awatt 2.856 GHz cyclotron autoresonance accelerator (CARA). A 90-100 k V, 2-3 MW linear electron beam has had up to 6.6 MW added to it in CAR A, with an rf-to-beam power efficiency of up to 96%. This efficiency l evel is larger than that reported for any fast-wave interaction betwee n radiation and electrons, and also larger than that in normal conduct ing rf linear accelerators. The results obtained are in good agreement with theoretical predictions.