Results of hydrogen pellet injection into ISX-B

Technical Report · Mon Sep 01 04:00:00 EDT 1980

DOI:https://doi.org/10.2172/5176168· OSTI ID:5176168

Milora, S. L.; Foster, C. A.; Thomas, C. E.

High speed pellet fueling experiments have been performed on the ISX-B device in a new regime characterized by large global density rise in both ohmic and neutral beam heated discharges. Hydrogen pellets of 1 mm in diameter were injected in the plasma midplane at velocities exceeding 1 km/s. In low temperature ohmic discharges, pellets penetrate beyond the magnetic axis, and in such cases a sharp decrease in ablation is observed as the pellet passes the plasma center. Density increases of approx. 300% have been observed without degrading plasma stability or confinement. Energy confinement time increases in agreement with the empirical scaling tau/sub E/ approx. n/sub e/ and central ion temperature increases as a result of improved ion-electron coupling. Laser-Thomson scattering and radiometer measurements indicate that the pellet interaction with the plasma is adiabatic. Penetration to r/a approx. 0.15 is optimal, in which case large amplitude sawtooth oscillations are observed and the density remains elevated. Gross plasma stability is dependent roughly on the amount of pellet penetration and can be correlated with the expected temporal evolution of the current density profile.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5176168
• Report Number(s): ORNL/TM-7422
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700205* -- Fusion Power Plant Technology-- Fuel
Heating
& Injection Systems
ABLATION
CRYOGENIC FLUIDS
CRYOGENICS
ELEMENTS
FLUIDS
FUEL PELLETS
FUELS
HYDROGEN
INJECTION
INTAKE
ISX TOKAMAK
NONMETALS
PELLETS
PLASMA DENSITY
REACTOR FUELING
THERMONUCLEAR FUELS
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS