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Author(s):
R. Kanno, N. Nakajima, H. Sugama, M. Okamoto and Y. Ogawa
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Title:
Effects of Finite-beta and Radial Electric Fields on Neoclassical Transport in the Large Helical Device
Date of publication:
Jan. 1997
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Key words:
neoclassical transport, LHD finite-beta configuration, improvement by E x B drift, bifurcation of electric fields, DKES code
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Abstract:
Effects of finite-beta and radial electric fields on the neoclassical transport in the Large Helical Device are investigated with the DKES (Drift, Kinetic Equation Solver) code. In the finite-beta configuration, even orbits of deeply trapped particles deviate significantly from magnetic flux surfaces. Thus, neoclassical ripple transport coefficients in the finite-beta configuration are several times larger than those in the vacuum configuration under the same condition of temperatures and radial electric fields. When the plasma temperature is several keV, a bifurcation of the electric fields appears under the ambipolarity condition, and sufficient large radial electric fields can be generated. As a result, the E x B drift rectifies orbits of particles and improves significantly the transport coefficients in the finite-beta configuration.
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