POLOIDAL AND RADIAL VARIATIONS IN PLASMA TRANSPORT IN A LIMITER SCRAPE-OFF LAYER IN DITE
We describe measurements of Mach number, M, and electron density and temperature, n-e and T-e, in a limiter scrape-off layer. The aim was to investigate boundary transport when the ratio of electron-electron mean free path to the toroidal connection length between limiters (the toroidal Knudsen number, Kn-t) varied widely. The experiment was in the DITE tokamak in a beam heated, deuterium discharge, n-e, T-e and M being measured at various poloidal and radial positions, using electrostatic probes. The range of Kn-t was from 1.5 at the largest radii to 2.5X10**-2 at 0.25 m radius. The values of M were consistent with a simple parallel flow model, including gas puffing and recycling. The scaling of the density "e" folding thickness, DELTA-n was DELTA-n about T-e**08n-e**-0.65 - I-p**0.6 over the range 0.2 < Kn-t about 1.5. The radial diffusion coefficient inferred from these results ranges from 1 to 8 m**2s**-1 and the scaling of D-perpendicular is discussed.
Bibliographic Reference: JOURNAL OF NUCLEAR MATERIALS, VOL. 128 & 129 (1984), PP. 180-185
Record Number: 1989124059100 / Last updated on: 1987-01-01
Available languages: en