Electron-beam rocket acceleration of hydrogen pellets
A proof-of-principle device for characterizing electron-beam rocket pellet acceleration has been developed and operated during the last few years. Experimental data have been collected for thousands of accelerated hydrogen pellets under a variety of beam conditions. One intact hydrogen pellet was accelerated to a speed of 578 m/s by an electron beam of 10 kV, 0.8 A, and I ms. The collected data reveal the significant finding that the measured bum velocity of bare hydrogen pellets increases with the square of the beam voltage in a way that is qualitatively consistent with the theoretical prediction based on the neutral gas shielding (NGS) model. The measured bum velocity increases with the beam current or power and then saturates at values two to three times greater than that predicted by the NGS model. The discrepancy may result from low pellet strength and large beam-pellet interaction areas. Moreover, this feature may be the cause of the low measured exhaust velocity, which often exceeds the sonic velocity of the ablated gas. Consistent with the NGS model, the measured exhaust velocity increases in direct proportion to the beam current and in inverse proportion to the beam voltage. To alleviate the pellet strength problem, experiments have been performed with the hydrogen ice contained in a lightweight rocket casing or shell. Pellets in such sabots have the potential to withstand higher beam powers and achieve higher thrust-coupling efficiency. Some experimental results are reported and ways of accelerating pellets to higher velocity are discussed.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6816784
- Report Number(s):
- CONF-921129-2; ON: DE93002822
- Resource Relation:
- Conference: 39. national symposium of the American Vacuum Society, Chicago, IL (United States), 9-13 Nov 1992
- Country of Publication:
- United States
- Language:
- English
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FUEL PELLETS
ACCELERATION
TOKAMAK DEVICES
PELLET INJECTION
DIAGNOSTIC TECHNIQUES
ELECTRON BEAMS
ELECTRON GUNS
HYDROGEN
THERMONUCLEAR REACTOR FUELING
BEAMS
CLOSED PLASMA DEVICES
ELEMENTS
LEPTON BEAMS
NONMETALS
PARTICLE BEAMS
PELLETS
THERMONUCLEAR DEVICES
700460* - Fusion Technology- Heating & Fueling Systems
Fuels- (1992)