Particle Balance and Core Fueling Calculations in C-Mod
Abstract
Particle balance and core fueling in the Alcator C-Mod tokamak are investigated with data-constrained calculations of plasma and neutral transport in the edge, scrape-off-layer (SOL), and divertor. The data include those from SOL and divertor probes, divertor and midplane neutral pressures, and multichord D_α measurements. The calculations are carried out with B2.5 and DEGAS codes. In order to fit the measured ne and Te profiles, preliminary results indicate that the radial transport coefficients for both particles and energy must increase with distance into the SOL and an anti-pinch term in the radial particle flux aids in accounting for ion orbit loss to the limiters.(M. Umansky, et al., to be published in Physics of Plasmas) Core fueling is dominated by recycling from the limiters and the inner wall, with less than 25% from divertor recycling. Strong particle and energy reflection from the metallic surfaces results in significantly less SOL attenuation of neutrals (and correspondingly larger core fueling) than would be the case with graphite limiters.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- November 1998
- Bibcode:
- 1998APS..DPP.K6P31O