Boronization in DIII-D

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

OSTI ID:7205588

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,

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: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-89ER51114
• OSTI ID: 7205588
• 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 -- Plasma Confinement-- (1992-)
700420* -- Fusion Technology-- Plasma-Facing Components-- (1992-)
BORON
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
CLOSED PLASMA DEVICES
CONFINEMENT
CONFINEMENT TIME
DEPOSITION
DOUBLET-3 DEVICE
ELECTRON DENSITY
ELECTRON TEMPERATURE
ELEMENTS
FILMS
H-MODE PLASMA CONFINEMENT
IMPURITIES
ION TEMPERATURE
PLASMA CONFINEMENT
PLASMA IMPURITIES
SEMIMETALS
SURFACE COATING
THERMONUCLEAR DEVICES
THERMONUCLEAR REACTOR FUELING
THIN FILMS
TOKAMAK DEVICES