RF extraction issues in the relativistic klystron amplifiers
- Naval Research Lab., Washington, DC (United States). Plasma Physics Division
Relativistic Klystron Amplifiers (RKAs) were successfully operated at NRL in several frequency regimes and power levels. In particular, an L-band RKA was optimized for high-power RF extraction into the atmosphere and an S-band RKA was operated, both in a two-beam and a single beam configuration. At L-band the RF extraction at maximum power levels ({>=}15 GW) was hindered by pulse shortening and poor repeatability. Only when the output power level was reduced to below {approximately}6GW did the L-band RKA deliver a flat-top RF pulse. Preliminary investigation showed electron emission in the radiating horn, due to very high voltages associated with the multi-gigawatt RF power levels. This electron current constituted an electric load in parallel with the radiating antenna, and precipitated the RF pulse collapse. At S-band the peak extracted power reached 1.7 GW with power efficiency {approximately}50%. However, pulse shortening limited the duration to {approximately}50 nanoseconds. The new triaxial RKA, currently in the final stages of construction, promises to solve many of the existing problems and to extend the frequency domain to 10 GHz, with power output in the 10`s of GW.
- OSTI ID:
- 51837
- Report Number(s):
- CONF-940142--; ISBN 0-8194-1449-2
- Country of Publication:
- United States
- Language:
- English
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