Self-sustained annihilation of magnetic islands in helical plasmas
- National Institute for Fusion Science, Toki 509-5292 (Japan)
The evolution of the magnetic island which is induced by the resonant deformation by external currents in helical systems (such as the large helical device (LHD) [A. Iiyoshi, Phys. Plasmas 2, 2349 (1995)]) is analyzed. The defect of the bootstrap current, caused by the magnetic island, has a parity which reduces the size of the magnetic island, if the bootstrap current enhances the vacuum rotational transform. The width of magnetic island can be suppressed to the level of ion banana width if the pressure gradient exceeds a threshold value. This island annihilation is self-sustained. That is, the annihilation continues, for fixed beta value, until the external drive for island generation exceeds a threshold. The effects of the reversal of the direction of the bootstrap current and of the sign of radial electric field are also investigated. The possibility of the neoclassical tearing mode in the LHD-like plasma is discussed.
- OSTI ID:
- 20764400
- Journal Information:
- Physics of Plasmas, Vol. 12, Issue 7; Other Information: DOI: 10.1063/1.1946731; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANNIHILATION
BANANA REGIME
BOOTSTRAP CURRENT
CHARGED-PARTICLE TRANSPORT
ELECTRIC FIELDS
ION COLLISIONS
LHD DEVICE
MAGNETIC CONFINEMENT
MAGNETIC ISLANDS
NEOCLASSICAL TRANSPORT THEORY
PLASMA
PLASMA PRESSURE
PRESSURE GRADIENTS
ROTATIONAL TRANSFORM
STELLARATORS
TEARING INSTABILITY