Studies of instability and transport in tokamak plasmas with very weak magnetic shear

Technical Report · Tue Apr 01 04:00:00 EST 1997

DOI:https://doi.org/10.2172/481609· OSTI ID:481609

Dong, J Q; Zhang, Y Z ^[1]; Mahajan, S M ^[2]

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1. Southwestern Inst. of Physics, Chengdu (China)
2. Texas Univ., Austin, TX (United States). Inst. for Fusion Studies

Ion temperature gradient (ITG or {eta}{sub i}) driven microinstabilities are studied, using kinetic theory, for tokamak plasmas with very weak (positive or negative) magnetic shear (VWS). The gradient of magnetic shear as well as the effects of parallel and perpendicular velocity shear (v{prime}{sub {parallel}} and v{prime}{sub E}) are included in the defining equations. Two eigenmodes: the double (D) and the global (G) are found to coexist. Parametric dependence of these instabilities, and of the corresponding quasilinear transport is systematically analyzed. It is shown that, in VWS plasmas, a parallel velocity shear (PVS) may stabilize or destabilize the modes, depending on the individual as well as the relative signs of PVS and of the gradient of magnetic shear. The quasilinear transport induced by the instabilities may be significantly reduced with PVS in VWS plasmas. The v{prime}{sub E} values required to completely suppress the instabilities are much lower in VWS plasmas than they are in normal plasmas. Possible correlations with tokamak experiments are discussed.

• Research Organization: Texas Univ., Austin, TX (United States). Inst. for Fusion Studies
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States); National Natural Science Foundation of China, Beijing, BJ (China); International Centre for Theoretical Physics, Trieste (Italy)
• DOE Contract Number: FG03-96ER54346
• OSTI ID: 481609
• Report Number(s): DOE/ER/54346--784; IFSR--784; ON: DE97007557
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CHARGED-PARTICLE TRANSPORT
DRIFT INSTABILITY
PLASMA DRIFT
PLASMA SIMULATION
SHEAR
STABILIZATION
THEORETICAL DATA
TOKAMAK DEVICES