Current-interchange tearing modes: Conversion of interchange-type modes to tearing modes

Journal Article · Sat May 15 00:00:00 EDT 2010 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3425857· OSTI ID:21371124

Zheng, L J ^[1]; Furukawa, M ^[2]

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1. Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)
2. Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8561 (Japan)

It is shown that, in addition to usual neoclassical tearing modes, another type of nonclassical tearing mode exists in tokamaks: viz., current-interchange tearing modes (CITMs). CITMs are directly driven by unstable pressure-driven electromagnetic or electrostatic modes of the interchange type (e.g., interchange/ballooning modes, drift waves, etc.) due to the current gradient in tokamaks. Interchange-type modes exchange not only thermal and magnetic energies between flux tubes but also current. In a plasma with a current (or resistivity) gradient, such an interchange can create a current sheet at a mode resonance surface and result in the excitation of CITMs. Note that the interchange mode (i.e., Rayleigh-Taylor instability) is fundamental to tokamak physics. This new theory has an effect on both resistive magnetohydrodynamic stability and transport theories. Instabilities of the interchange type could be directly converted into CITMs, alternative to forming turbulent eddies through nonlinear coupling as in conventional transport theories. In particular, our CITM theory fills in the component in the transport theory of Rechester and Rosenbluth [Phys. Rev. Lett. 40, 38 (1978)] for the origin of magnetic island structure in axisymmetric tokamaks.

• OSTI ID: 21371124
• Journal Information: Physics of Plasmas, Vol. 17, Issue 5; Other Information: DOI: 10.1063/1.3425857; (c) 2010 American Institute of Physics; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BALLOONING INSTABILITY
ELECTRIC CURRENTS
MAGNETIC ISLANDS
MAGNETOHYDRODYNAMICS
RAYLEIGH-TAYLOR INSTABILITY
TEARING INSTABILITY
TOKAMAK DEVICES
TRANSPORT THEORY
WAVE PROPAGATION
CLOSED PLASMA DEVICES
CURRENTS
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
MAGNETIC FIELD CONFIGURATIONS
MECHANICS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
THERMONUCLEAR DEVICES