Boronization in DIII-D

Conference · Fri May 01 04:00:00 EDT 1992

OSTI ID:10162242

Jackson, G L; Burrell, K H; DeBoo, J C; Greenfield, C M; Groebner, R J; Hodapp, T; Kellman, A G; Lee, R; Lippman, S I; Phillips, J; Taylor, T S; West, W P ^[1]; Winter, J ^[2]; Moyer, R ^[3]; Watkins, J ^[4]

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1. General Atomics, San Diego, CA (United States)
2. Kernforschungsanlage Juelich GmbH (Germany). Inst. fuer Plasmaphysik
3. California Univ., Los Angeles, CA (United States)
4. Sandia National Labs., Livermore, CA (United States)

A thin boron film has been applied to the DIII-D tokamak plasma facing surfaces to reduce impurity influx, particularly oxygen and carbon. A direct result of this surface modification was the observation of a regime of very high energy confinement, VH-mode, with confinement times from 1.5 to 2 times greater than predicted by H-mode scaling relation for the same set of parameters. VH-mode discharges are characterized by low ohmic target densities, low edge neutral pressure, and reduced cycling. These conditions have reduced the collisionality, {nu}*, in the edge region producing a higher edge pressure gradient and a significant bootstrap current, up to 30% of the total current. We will describe the edge plasma properties after boronization including reductions in recycling inferred from measurements of {tau}{sup p}*. In particular we will discuss the edge plasma conditions necessary for access to VH-mode including the boronization process and properties of the deposited film.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-89ER51114
• OSTI ID: 10162242
• Report Number(s): GA-A--20904; CONF-920311--19; ON: DE92016249
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700310
700420
BORON
CHEMICAL VAPOR DEPOSITION
CONFINEMENT TIME
DOUBLET-3 DEVICE
ELECTRON DENSITY
ELECTRON TEMPERATURE
H-MODE PLASMA CONFINEMENT
ION TEMPERATURE
PLASMA CONFINEMENT
PLASMA IMPURITIES
PLASMA-FACING COMPONENTS
SURFACE COATING
THERMONUCLEAR REACTOR FUELING
THIN FILMS