Title :
Effects of tapered tubes on long-pulse microwave emission from intense e-beam gyrotron-backward-wave-oscillators
Author :
Walter, M.T. ; Gilgenbach, R.M. ; Menge, P.R. ; Spencer, T.A.
Author_Institution :
Dept. of Nucl. Eng., Michigan Univ., Ann Arbor, MI, USA
fDate :
10/1/1994 12:00:00 AM
Abstract :
Experiments are reported on tapered-tube versus uniform-tube, gyrotron-backward-wave-oscillators (4.5-6 GHz) driven by an intense electron beam with parameters: 0.8 MV, 1-4 kA, and pulselength (0.5-1 μs). Results show that, compared to a uniform interaction tube, a gyro-BWO with a 10% downtapered tube produces the following effects: 1) highest microwave peak-power (up to about 100 MW in internal tube), a factor of 2 higher than the uniform tube, 2) more reproducible long-pulse (400-500 ns) emission, and 3) the largest inferred-integrated energy (factor of 2.5-3 increase). Experiments show high power microwave spikes with lower power plateaus. Experimental observations are in qualitative agreement with MAGIC code simulations of uniform and tapered-tube gyro-BWO´s
Keywords :
backward wave oscillators; electron beams; gyrotrons; microwave generation; microwave oscillators; 0.5 to 1 mus; 0.8 MV; 1 to 4 kA; 100 MW; 4.5 to 6 GHz; 400 to 500 ns; MAGIC code simulations; downtapered tube; gyro-BWO; gyrotron-backward-wave-oscillators; high power microwave spikes; inferred-integrated energy; intense electron beam; long-pulse emission; long-pulse microwave emission; microwave peak-power; power plateaus; tapered tubes; uniform tubes; Cathodes; Diodes; Electromagnetic heating; Electron beams; Frequency; Klystrons; Magnetic fields; Plasma accelerators; Solids; Voltage;
Journal_Title :
Plasma Science, IEEE Transactions on
