On the nature of rotational shear stabilization in toroidal geometry and its numerical representation

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · Physics of Plasmas; (United States)

DOI:https://doi.org/10.1063/1.870522· OSTI ID:7130797

Miller, R L; Waltz, R E ^[1]

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1. General Atomics, San Diego, California 92186-9784 (United States)

In this paper a simple one-dimensional model problem is treated as a paradigm for understanding the nature of rotational shear stabilization in toroidal geometry and its numerical representation. The model is first formulated in a ballooning mode angle [theta][sub 0] space, where the convective nature of the stabilization is clear. If [theta][sub 0] is treated as a continuum variable, the slightest rotational shear eventually convects a ballooning mode through both the unstable and stable poloidal angles of a torus, resulting in a stable slab-like time-averaged growth rate and eigenmode growth rate. However, if [theta][sub 0] is treated as a discrete variable, unstable eigenmodes remain at weak velocity shear. By transforming to real [ital X] space, we are able to physically interpret these unstable modes. Continuous [theta][sub 0] formulations correspond to a radially infinite box and discrete [theta][sub 0] formulations correspond to a finite box. If care is taken to make the rotational shear constant throughout the whole box, the unstable eigenmodes are found to be localized to the edge and the stable continuum-like modes are localized but distributed throughout the interior. In the case of constant rotational shear, it is found that a critical rotational shear exists for complete toroidal stabilization independent of representation (continuous or discrete [theta][sub 0]) or box size.

• DOE Contract Number: FG03-92ER54150
• OSTI ID: 7130797
• Journal Information: Physics of Plasmas; (United States), Journal Name: Physics of Plasmas; (United States) Vol. 1:9; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
ANNULAR SPACE
BALLOONING INSTABILITY
CLOSED CONFIGURATIONS
CLOSED PLASMA DEVICES
CONFIGURATION
EIGENSTATES
INSTABILITY
MAGNETIC FIELD CONFIGURATIONS
MECHANICAL PROPERTIES
NUMERICAL SOLUTION
ONE-DIMENSIONAL CALCULATIONS
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
ROTATING PLASMA
SHEAR PROPERTIES
SPACE
STABILIZATION
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TOROIDAL CONFIGURATION