Visible continuum measurements on the Alcator C Tokamak: Changes in particle transport during pellet fuelled discharges

Technical Report · Mon Dec 01 04:00:00 EST 1986

OSTI ID:6016646

Foord, M E

A spatially resolving visible light detector system is used to measure continuum radiation near 5360A on the Alcator C Tokamak. For the typically hot plasmas studied, the continuum emission is found to be dominated by bremsstrahlung radiation near this wavelength region. Accurate determinations of Z/sub eff/ are obtained from continuum measurements using independently determined temperature and density measurements. Density profiles during high density, clean pellet fueled discharges, are also determined and are used to study the changes in particle transport after injection. For discharges with sufficiently large pellet density increases, density profiles are found to become more peaked following the injection. In these cases, the profiles are found to remain peaked for the remainder of the discharge, or until a ''giant'' sawtooth or minor disruption abruptly returns the profiles to a flatter pre-pellet condition. Analysis of density profiles after pellet injection yields information about the radial diffusion and convection velocity of the plasma particles. The peakedness in the density profiles, observed after pellet injection, is attributable mostly to increases in inward convection. It is concluded that neoclassical fluxes are too small to account for these changes. 70 refs., 55 figs.

• Research Organization: Massachusetts Inst. of Tech., Cambridge (USA). Plasma Fusion Center
• DOE Contract Number: AC02-78ET51013
• OSTI ID: 6016646
• Report Number(s): DOE/ET/51013-210-Rev.; PFC/RR-87-2-Rev.; ON: DE88002293
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700102* -- Fusion Energy-- Plasma Research-- Diagnostics
ALCATOR DEVICE
BREMSSTRAHLUNG
CLOSED PLASMA DEVICES
COLLISIONLESS PLASMA
ELECTRIC CONDUCTIVITY
ELECTRIC HEATING
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
ELECTRON DENSITY
EMISSION SPECTRA
HEATING
IMPURITIES
IONIZING RADIATIONS
JOULE HEATING
MEASURING INSTRUMENTS
PELLET INJECTION
PHYSICAL PROPERTIES
PLASMA
PLASMA DIAGNOSTICS
PLASMA HEATING
RADIATION DETECTORS
RADIATIONS
RESISTANCE HEATING
SOFT X RADIATION
SPECTRA
STEADY-STATE CONDITIONS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRANSPORT THEORY
X RADIATION