Modeling of particle and energy transport in the edge plasma of Alcator C-Mod
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
In the present study recycling and transport in the edge plasma of Alcator C-Mod [I. H. Hutchinson {ital et al.}, Phys. Plasmas {bold 1}, 1511 (1994)] is modeled and analyzed with the multi-fluid code UEDGE [T. D. Rognlien {ital et al.}, J. Nucl. Mater. {bold 196{endash}198}, 347 (1992)]. Matching the experimental plasma density profiles in the scrape-off layer (SOL) requires a spatially dependent effective anomalous diffusion coefficient D{sub {perpendicular}} growing rapidly towards the wall. The midplane pressure of neutral gas, P{sub mid}, is a key parameter that reflects the magnitude of anomalous transport of plasma from the core. Recycling of plasma on the main chamber wall appears to be quite significant, especially in the case of high P{sub mid}{approximately}0.3 mTorr when the main wall provides {approximately}70{percent} of recycling neutrals in the main chamber. In the upper SOL (well above the {ital x} point) draining of particles by the poloidal flow is weak and thus the particle balance is predominantly radial. For the radial heat transport it is found that energy flux carried by radial plasma convection and by charge-exchange (CX) neutrals is quite significant in SOL. In the high P{sub mid} case, heat conduction by CX neutrals along with radial heat convection by plasma carries most of the power flux ({approximately}75{percent}) across the last closed flux surface. Even in the low P{sub mid} case, heat conduction by CX neutrals dominates the radial heat flux far out in the SOL. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 349355
- Journal Information:
- Physics of Plasmas, Vol. 6, Issue 7; Other Information: PBD: Jul 1999
- Country of Publication:
- United States
- Language:
- English
Similar Records
Erosion/redeposition analysis of the ITER first wall with convective and non-convective plasma transport
Characterization of a partially-ionized, detached, divertor plasma