Nonlinear stability and evolution of drift-tearing modes

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5223407

Scott, B D

The question of the nonlinear stability and subsequent evolution of drift-tearing modes in tokamak-like environments is considered. The tearing mode and the drift physics are introduced, and a brief review of previous work given. A set of reduced equations for the drift-tearing mode is derived from two-fluid magnetohydrodynamics. The equations are specialized for small, nonlinear magnetic islands in slab geometry. These are used to scrutinize the results of linear stability theory in light of nonlinear physics arising from the effect of the mode on the equilibrium density and temperature profiles. It is shown that linearly growing drift-tearing modes are rendered stable at a very small island, width by quasilinear thermal effects. However, both linearly and quasilinearly stabilized modes grow to large amplitude if the initial island width is larger than the linear tearing layer, demonstrating the importance of nonlinear considerations in predictions of stability. Having concluded that drift-tearing modes will in fact be seen in present and near-future thermal regimes, their evolution is addressed.

• Research Organization: Maryland Univ., College Park (USA)
• OSTI ID: 5223407
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
CLOSED PLASMA DEVICES
DRIFT INSTABILITY
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
MAGNETOHYDRODYNAMICS
MECHANICS
NONLINEAR PROBLEMS
ORIGIN
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PLASMA MICROINSTABILITIES
SLABS
STABILITY
TEARING INSTABILITY
THERMONUCLEAR DEVICES
TOKAMAK DEVICES