Influence of vacuum toroidal field on two-fluid flowing equilibria of helicity-driven spherical torus plasmas
- Department of Maritime Science and Technology, Japan Coast Guard Academy, 5-1 Wakaba, Kure, Hiroshima 737-8512 (Japan)
Two-fluid flowing equilibrium configurations of a helicity-driven spherical torus (HD-ST) in the realistic confinement region, including a flux conserver and a coaxial helicity source, are numerically determined by means of the combination of the finite difference and the boundary element methods. It is found from the numerical results that electron fluid near the central conductor is tied to a vacuum toroidal field and ion fluid is not. The magnetic configurations change from the high-q HD-ST (safety factor, q>1) with a paramagnetic toroidal field and low-{beta} (volume average {beta} value, <{beta}>{approx_equal}2%) through the helicity-driven spheromak and reversed-field pinch to the ultra-low-q HD-ST (0<q<1) with a diamagnetic toroidal field and high-{beta} (<{beta}>{approx_equal}18%) as the vacuum toroidal field at the inner edge regions decreases and reverses the sign. The two-fluid effects are more significant in this equilibrium transition when the ion diamagnetic drift has the same direction as the ExB one.
- OSTI ID:
- 20860129
- Journal Information:
- Physics of Plasmas, Vol. 13, Issue 7; Other Information: DOI: 10.1063/1.2231685; (c) 2006 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
BOUNDARY ELEMENT METHOD
BOUNDARY LAYERS
ELECTROMAGNETIC FIELDS
ELECTRONS
EQUILIBRIUM
FINITE DIFFERENCE METHOD
FLUIDS
HELICITY
IONS
PARAMAGNETISM
PLASMA
PLASMA CONFINEMENT
PLASMA DIAMAGNETISM
RADIATION TRANSPORT
REVERSE-FIELD PINCH
REVERSED-FIELD PINCH DEVICES
SPHERICAL CONFIGURATION
SPHEROMAK DEVICES