Analysis of the mode composition of an X-band overmoded O-type Cerenkov high-power microwave oscillator
- College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)
Overmoded slow wave structures (SWSs) with large diameter are utilized in O-type Cerenkov high-power microwave (HPM) sources for their high power capacity. However, multi-modes may be output simultaneously in the overmoded O-type Cerenkov HPM sources. In order to achieve high mode purity, the mode composition of the output power should be analyzed quantitatively when the structure of this type of device is being optimized. Two accurate numerical methods of making quantitative analysis of the mode composition in particle-in-cell model are introduced in this paper. And then, the mode composition of an X-band O-type Cerenkov oscillator with overmoded SWSs (D/{lambda} Almost-Equal-To 2.7) is analyzed. The analysis indicates that appropriate selection of the parameters of overmoded SWSs and electron beam is important, as mentioned in previous reports, for realizing mode selection in beam-wave interaction. Besides, designing of the mode conversion effect, which is rarely discussed, can also affect the mode purity of output power. After adjustment of the dimensions of the tapered waveguide, which converts the combination of 'surface wave' and 'volume wave' to the 'volume wave' in the output waveguide, the percentage of total output microwave power carried by the TM{sub 01} mode is higher than 95% in the X-band overmoded Cerenkov oscillator at the diode voltage ranging from 570 kV to 750 kV.
- OSTI ID:
- 22068838
- Journal Information:
- Physics of Plasmas, Vol. 19, Issue 10; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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