Impurity penetration and transport during VH-mode on DIII-D
A new modeling effort is made in order to understand the observed relatively low levels of impurity contamination during the VH-mode phase on DIII-D, as compared to those observed during the H-mode phase of selected discharges. The key element is the inclusion of the real 2-D flux surface geometry in the prediction of impurity penetration of sputtered atoms through the scrape-off layer into the core plasma. Of the elements which determine the impurity content in the plasma: sputtering yield, penetration, and core transport, the penetration through the scrape-off layer is found to be the most determinative factor. The low impurity content in VH-mode is attributed to the development of a scrape-off layer with higher density and temperature properties than those normally obtained in H-mode.
- Research Organization:
- General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-89ER51114
- OSTI ID:
- 5257237
- Report Number(s):
- GA-A-20903; CONF-920311--13; ON: DE92014233
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
700330* -- Plasma Kinetics
Transport
& Impurities-- (1992-)
CHARGED-PARTICLE TRANSPORT
CLOSED PLASMA DEVICES
CONFINEMENT
CONFINEMENT TIME
DOUBLET-3 DEVICE
ELECTRON TEMPERATURE
H-MODE PLASMA CONFINEMENT
IMPURITIES
PLASMA CONFINEMENT
PLASMA IMPURITIES
RADIATION TRANSPORT
SPUTTERING
THERMONUCLEAR DEVICES
TOKAMAK DEVICES