Microinstability properties of negative magnetic shear discharges in the Tokamak Fusion Test Reactor and DIII-D
- Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543-0451 (United States)
- General Atomics, San Diego, California 92186-9784 (United States)
The microinstability properties of discharges with negative (reversed) magnetic shear in the Tokamak Fusion Test Reactor (TFTR) [R. J. Hawryluk {ital et al.}, {ital Plasma Physics and Controlled Nuclear Fusion Research, 1994} (International Atomic Energy Agency, Vienna, 1995), Vol. 1, p. 11] and DIII-D [R. D. Stambaugh for the DIII-D Team, {ital Plasma Physics and Controlled Nuclear Fusion Research, 1994} (International Atomic Energy Agency, Vienna, 1995), Vol. 1, p. 83] experiments with and without confinement transitions are investigated. A comprehensive kinetic linear eigenmode calculation employing the ballooning representation is employed with experimentally measured profile data, and using the corresponding numerically computed magnetohydrodynamic (MHD) equilibria. The instability considered is the toroidal drift mode (trapped-electron-{eta}{sub i} mode). A variety of physical effects associated with differing q-profiles are explained. In addition, different negative magnetic shear discharges at different times in the discharge for TFTR and DIII-D are analyzed. The effects of sheared toroidal rotation, using data from direct spectroscopic measurements for carbon, are analyzed using comparisons with results from a two-dimensional calculation. Comparisons are also made for nonlinear stabilization associated with shear in E{sub r}/RB{sub {theta}}. The relative importance of changes in different profiles (density, temperature, q, rotation, etc.) on the linear growth rates is considered. {copyright} {ital 1997 American Institute of Physics.}
- Research Organization:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- DOE Contract Number:
- AC02-76CH03073; AC03-89ER51114
- OSTI ID:
- 538474
- Journal Information:
- Physics of Plasmas, Vol. 4, Issue 9; Other Information: PBD: Sep 1997
- Country of Publication:
- United States
- Language:
- English
Similar Records
Microinstability properties of negative magnetic shear discharges in the Tokamak Fusion Test Reactor and DIII-D
Rotational and magnetic shear stabilization of magnetohydrodynamic modes and turbulence in DIII-D high performance discharges