Wall intersection of ion orbits induced by fast transport of pedestal plasma over an electrostatic potential hill in a tokamak plasma edge
- Department of Physics, Korea Advanced Institute of Science and Technology, Yusong-Ku, Daejon, Korea 305-701 (Korea, Republic of)
An edge localized mode event is known to transport a significant portion of pedestal plasma across the separatrix and increase the divertor heat load to a possibly intolerable level in a tokamak fusion reactor. In the present work, a large random-walk transport is introduced in a plasma edge in a guiding-center orbit following code XGC [C. S. Chang, S. H. Ku, and H. Weitzner, Phys. Plasmas 11, 2649 (2004)] to understand the effect of edge radial electric-field shear on the wall-intersection location of large-transport orbits. It is found that without an edge radial electric field, E{sub r}, the majority of large-diffusion-induced ion orbital loss is to the outer divertor near the separatrix surface. However, with a large negative E{sub r} in the plasma edge with the ion grad-B drift into the single-null divertor, ion orbits with their kinetic energy less than the potential energy shift their wall-intersection locations to the inner divertor, while those with their kinetic energy higher than the potential energy retain their wall intersections at the outer divertor. If the ion grad-B is away from the single-null divertor, the ion orbital loss is always to the outer wall.
- OSTI ID:
- 20702247
- Journal Information:
- Physics of Plasmas, Vol. 12, Issue 10; Other Information: DOI: 10.1063/1.2052487; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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