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Neutrals Studies on Alcator C-Mod
- Source :
- Fusion Science and Technology. 51:390-400
- Publication Year :
- 2007
- Publisher :
- Informa UK Limited, 2007.
-
Abstract
- The high neutral densities and short neutral mean-free-paths in theAlcator C-Mod divertor have provided a unique testing ground for our understanding of the role of neutrals in a tokamak. The high neutral pressures found in the C-Mod divertor can be reproduced in models only by including such processes as ion-neutral and neutral-neutral collisions and neutral viscosity, as well as taking into account the plasma in the private flux region. After detachment, when the divertor plate ion flux has dropped by more than an order of magnitude, the divertor pressure still remains high. High neutral collisionality and the plasma in the private flux region again help keep neutrals in the divertor along with the large source of neutrals due to recombination. Likewise, diffusive neutrals are the explanation for the divertor neutral pressure's insensitivity to strike point position. Closure of neutral leakage pathways did not lead to a decrease in neutral pressures in the region outside the divertor-the main chamber. This observation prompted further research, which showed that ion fluxes to main chamber surfaces rival those reaching the divertor plates; the main chamber pressure can be primarily determined by the level of ion transport perpendicular to the magnetic field. This finding has spawned a host of studies (active and passive) both at C-Mod and other tokamaks to understand how radial transport can be so large.
- Subjects :
- Physics
Nuclear and High Energy Physics
Tokamak
020209 energy
Mechanical Engineering
Divertor
02 engineering and technology
Plasma
Collisionality
01 natural sciences
010305 fluids & plasmas
Magnetic field
Ion
Chamber pressure
law.invention
Nuclear Energy and Engineering
Alcator C-Mod
law
0103 physical sciences
0202 electrical engineering, electronic engineering, information engineering
General Materials Science
Atomic physics
Civil and Structural Engineering
Subjects
Details
- ISSN :
- 19437641 and 15361055
- Volume :
- 51
- Database :
- OpenAIRE
- Journal :
- Fusion Science and Technology
- Accession number :
- edsair.doi...........be434946b649112d8c939937fc96669d