Magnetic tapering of intense e-beam, long-pulse gyro-BWOs
- Univ. of Michigan, Ann Arbor, MI (United States). Intense Energy Beam Interaction Lab.
Experiments have been performed to investigate the effects of tapered magnetic fields on the high power microwave emission from the gyrotron-backward-wave-oscillator (gyro-BWO). Tapering trimcoils have been utilized to compare gyro-BWO microwave emission for uniform versus tapered magnetic fields in the range of {Delta}B/B{sub 0} = 10--15%, where B{sub 0} = 4--6 kG. These magnetic tapering experiments employed a TE{sub 11} mode at tunable-frequency of 4.5--6 GHz, with a uniform interaction tube radius. Initial experimental results show that the peak microwave power and integrated energy are nearly the same for the uniform magnetic field, compared to the 11% downtapered B field. Uptapered magnetic fields ({approximately}15%) gave lower powers and energies. MAGIC code simulations have been run for the gyro-BWO with a scaled TE{sub 01} mode to model various magnetic tapering magnitudes and both directions. Future gyro-BWO experiments will combine tapered tube radius with magnetic tapering to optimize microwave emission power, pulselength, and energy.
- OSTI ID:
- 51772
- Report Number(s):
- CONF-940604--; ISBN 0-7803-2006-9
- Country of Publication:
- United States
- Language:
- English
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