| 摘要 |
PURPOSE:To obtain high efficiency by transmitting and focusing an electromagnetic wave in a single direction while electrically recovering electromagnetic energy. CONSTITUTION:The electromagnetic wave of an electron beam 19 is oscillated and amplified by the partially transmissive mirror 22 for being transmitted in the direction of a mirror 23. The reflection face of the mirror 23 has an oval face 40 having two focal points, namely the center 37 of a partially transmissive mirror 22 and the center 39 of the reflection face 38 of a mirror 24. Similarly, the mirror 24 has two focal points, namely the center 41 of the mirror 23 and the center 43 of the reflection face 42 of the mirror 24 while the electromagnetic wave reflected on the reflection face 38 is reflected on the reflection face 42 for being transmitted in the direction of the mirror 25. Also the mirror 25 has the reflection faces 44 and 45 for transmitting the electromagnetic wave in the Z-direction while the reflection face 45 is formed into an oval rotary face focusing on the plasma 46. Further, an electron recovery electrode 26 is impressed with the potential V1 lower than the potential V of the axially symmetrical partially transmissive mirror 22 and higher than the potential V4 of the thermal cathode of an electron gun 20, while the potential V2 of the secondary electron suppressing electrode 47 is made to be lower than potential of an electron recovery electrode 26 and higher than the potential of an electron gun 20 thus being able to electrically recover the energy held by the electron beam. |
