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Highly elongated, low‐aspect‐ratio tokamak produced by negative‐biased theta pinch
Author(s) -
Narushima Yoshiro,
Takahashi Tsutomu,
Nogi Yasuyuki
Publication year - 2001
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/1520-6416(200103)134:4<19::aid-eej3>3.0.co;2-n
Subject(s) - tokamak , toroid , aspect ratio (aeronautics) , physics , plasma , pinch , electromagnetic coil , spherical tokamak , safety factor , reversed field pinch , magnetohydrodynamics , mechanics , displacement (psychology) , magnetic field , atomic physics , toroidal field , current (fluid) , nuclear magnetic resonance , nuclear physics , psychology , optoelectronics , quantum mechanics , psychotherapist , thermodynamics
Ultra Low Aspect Ratio Tokamaks (ULART) are produced by using a negative‐biased theta‐pinch device. A slender conducting rod which serves as a toroidal field coil is newly installed along a geometrical center axis of the theta‐pinch coil. The ULART is quickly formed for about 10 μs by applying programmed current flows from three sets of fast banks and a slow bank to these coils and is sustained for about 100 μs. The plasma diagnosed from a magnetic probe array has a low aspect ratio A = 1.1 and a poloidal surface with a high elongation ratio κ = 10. The safety factor reaches about 30 near the separatrix edge when I p = 280 kA flows in the plasma and I tfc = 30 kA in the conducting rod. A preliminary result on global MHD characteristics of the ULART is also given. The plasma is unstable with respect to a vertical displacement and a toroidal n = 1 mode. The amplitudes of these modes depend on the values of I tfc and κ. © 2001 Scripta Technica, Electr Eng Jpn, 134(4): 19–27, 2001