Geometrical influences on neoclassical magnetohydrodynamic tearing modes
- Department of Nuclear Engineering and Engineering Physics, 1500 Engineering Drive Madison, Wisconsin 53706-1687 (United States)
The influence of geometry on the pressure drives of nonideal magnetohydrodynamic tearing modes is presented. In order to study the effects of elongation, triangularity, and aspect ratio, three different machines are considered to provide a range of tokamak configurations: Tokamak Fusion Test Reactor (circular) [Fusion Technol. {bold 21}, 1324 (1992)], DIII-D (D-shaped) [{ital Plasma Physics and Controlled Nuclear Fusion Research 1986} (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 159], and Pegasus (extremely low aspect ratio) [Fonck {ital et al.}, Bull. Am. Phys. Soc. {bold 41}, 1400 (1996)]. For large aspect ratio tokamaks, shaping does very little to influence the pressure gradient drives, while at low aspect ratios, a very strong sensitivity to the profiles is found. In particular, this sensitivity is connected to the strong dependence on the magnetic shear. This suggests that at low aspect ratio it may be possible to stabilize neoclassical tearing modes by a flattening the q profile near low order rational surfaces (e.g., q=2/1) using a combination of shaping and localized current drive, whereas at large aspect ratio it is more difficult. {copyright} {ital 1998 American Institute of Physics.}
- OSTI ID:
- 573966
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 2 Vol. 5; ISSN PHPAEN; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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