NRL quasioptical gyrotron program. Final report, November 1, 1991--October 31, 1993

Technical Report · Sun Jun 01 04:00:00 EDT 1997

DOI:https://doi.org/10.2172/491571· OSTI ID:491571

Fliflet, A

The quasioptical gyrotron (QOG) has been under development as a high power, tunable source for tokamak plasma heating applications. Given the critical importance of source efficiency for large-scale ESCH applications, understanding the causes of the low QOG efficiency and finding ways of improving it became a top priority for the current NRL program. The importance of the present work is that is represents new insight into the factors controlling the efficiency of quasioptical gyrotrons. The author has demonstrated that the technique of mode priming provides a method for improving efficiency via enhanced mode detuning and leads to more stable single-mode operation of highly over-moded resonators. The latter feature is an important consideration for output coupler and rf transmission system optimization and can make the QOG less sensitive to external influences such as window reflections. He has shown that a prebunching resonator is readily implemented in the quasioptical configuration. It is relatively free of the problems of spurious modes and cross-talk which plague over-moded prebunching cavities in conventional gyrotrons. The observation of almost 18% efficiency represents a doubling of the previous best single-mode results. Further improvements are expected from the optimization of start-up conditions and the study of the effects of the second harmonic interaction.

• Research Organization: Department of the Navy, Washington, DC (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States)
• DOE Contract Number: AI05-83ER52092
• OSTI ID: 491571
• Report Number(s): DOE/ER/52092--T7; NRL/MR/6793--93-7387; ON: DE97006648
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CAVITY RESONATORS
ECR HEATING
MICROWAVE AMPLIFIERS
OSCILLATION MODES
PERFORMANCE
PROGRESS REPORT
RESEARCH PROGRAMS
TOKAMAK DEVICES